I'm not confused and know the difference quite well.
Short lesson for you.
Historically the term is Forward Air Controller (FAC). This was and continued to be the term in general usage well into the war. Within NATO there are certain standards set and the universal STANAG within NATO was for FACs until 2016.
Up until the spring of 2002 the RCAF was responsible for FAC training in Canada but became bored with it (in fact they adopted the USAF post Gulf War belief that FACs were no longer relevant because of the effect that precision guided munitions brought to the game.) and turned the training over to the Royal Canadian School of Artillery. (As an aside the Army wasn't too happy with the product the RCAF was turning out anyway.) Artillery officers attending the Advanced Gunnery course and subsequently the FOO course were all trained as FACs (Your truly became one back in the seventies and in did a month in Germany as a member of a divisional TACP FACing my little heart out between beers).
A team of two artillery officers became Air to Ground Weapon Range Safety Officers and certified as both Canadian and NATO FAC Instructors and started rebuilding the Canadian FAC training system.
Just as the RCAS was defining and rewriting the training standards for the new and refreshed FAC course, the US around the fall of 2003 adopted the JTAC terminology and standards culminating in an MOA being signed between the US services. With that in play and the reality that in all probability in the light of the developing War on Terror that most aircraft to be dealt with would be American, the Canadian RCAS also moved towards certifying JTACs and signed the US JTAC MOU to ensure that all subsequent Canadian FACs would be JTAC certified. There is in fact a fairly rigorous certification process demanded under the MOU which is closely observed in theatre.
Over the next several years as the RCAS took charge of the process, the training at the school, the certification of brigade and TACP FACs and the establishment of a certification program within special forces took hold with the new FACs all qualifying to and certified as JTACs.
A problem occurred as a result of the A10 incident on Op Medusa. The resulting BOI/Ball Report pointed out that the forward air control in that incident wasn't a cause of the incident but that there were certain deficiencies. One key one was that the NATO STANAG didn't require training with live ordnance, attack helicopters or multiple sorties. It also made mention of the fact that for Canadian FOO/FACs, FACing was a secondary task.
Note that even before the report was out, the FAC/JTAC training for the next roto - 1-07 - was considered inadequate and it just so happened that part of that deploying roto included one of the instructors-in-gunnery who had been working at the RCAS on the FAC project for the last few years. Just before Christmas of 2006 he spun up a very major exercise in the US involving US helicopters, Canadian jets and US FAC trainers, a mortar platoon and all of the FOO/FACs who would deploy to get them fully JTAC certified.
In the aftermath of the BOI, several changes were made including an endorsement in July of 2007 by the CLS authorizing the attachment to each artillery regiment of 4 combat arms officers for FAC/FOO parties (their words, not mine) for a total of 9-12 PYs in addition to the existing 36 artillery FOO/FAC parties (again, the system's words, not mine). The resultant FAC/FOO party would consist of a combat arms officer (capt/lt) and an artillery senior NCO, both FAC qualified and two other gunners as driver/sigs. In contrast the the FOO/FAC party consists of an artillery capt FOO, an artillery sergeant FAC, and four other artillerymen. There was also a provision for the brigade TACP.
It's around this time too that terminology starts changing. Official documents still referred to the common term of FAC even though the certification was already under the JTAC MOU and the designation of an individual in the field was commonly as JTAC. FAC remained the NATO term under STANAG 3797 "Minimum Qualifications for Forward Air Controllers & Laser Operators for Forward Air Controllers" until it's title and content was changed to "Joint Terminal Attack Controller Program" in 2016.
The high water mark was when TF 1-10 deployed 13 JTACs on their roto. However, with the end of the war things started to go sour again. It costs a lot to make and keep a JTAC qualification - especially F-18 hours which the RCAF is loath to spend on lowly ground pounders. There's also a fairly high failure rate so from 2010 on there's a constant reevaluation as to how many courses need to be run and how many current JTACs are needed at any given time. Just as a statistic by 2015, Canada had trained a total of 267 JTACs at a cost of some $600,000 apiece to Limited Combat Ready status and an additional $400,000 to Combat Ready status. The retention rate was some 17%. The problem is that after training and initial deployment the individuals generally moved on to other aspects of their career.
By 2016 there were several pushes to resolve the issue - and that's roughly where my currency on the matter ends.
The math simply doesn't work. For the Army there were at that time 62 authorized JTAC positions yet the Army's throughput was 9 per year which meant that to keep positions filled a given person would need to spend on average 7 years in the job. They don't. Artillery officers spend roughly 2 years in the job as FOO so that's no longer a good fit. It's not much better for arty NCO techs as generally anyone smart enough to be a good JTAC will probably also get promoted out of the job fairly quickly. CSOR has a much better situation than the Army because an operator can spend quite some time in the job. So at this point, I'm not sure what direction the Army has gone with training FOOs as JTACs. I'll probably be speaking to someone who knows later this week and bring myself up to date.