Jasper is a special case where due to being in a national park with tightly controlled development permits, the municipal council had to be involved in the decision and required that Tesla install Universal DC fast chargers in addition to the Superchargers to avoid giving Tesla preferential treatment on government lands. Tesla requested 8 Superchargers, and the town wanted equal opportunity for other electric vehicles, and it was decided that an 8 Tesla to 3 non-Tesla ratio of chargers approximates the Tesla to non-Tesla vehicles on the road at the time of the application.
Since Universal chargers were mandatory for Tesla to install any Superchargers in Jasper, and the NRCan funding was available, this probably started this whole round of NRCan funded Tesla chargers with this unique Tesla & Universal requirement, since if they had to do it for one, they might as well do it for more.
You can read up on this in the Jasper thread - the municipal council meeting minutes is interesting reading and the video conference had some good insight to the reasoning for the decisions made. The behind-the scenes information with the planning and costs of DC charging are especially eye opening.
Municipality of Jasper is looking at dedicating a section of a car park to electric vehicle charging and has a proposal from Tesla to install 8x V3 stalls on the table: https://www.jasper-alberta.com/ArchiveCenter/ViewFile/Item/821 It appears they want to set aside a dedicated EV charging...
teslamotorsclub.com
In any case, the following are my thoughts for the reasoning of 6+2 here and 8+3 in Jasper.
As an example for previous Supercharger installations, the Trans-Canada 1 Supercharger installations are mostly 6 stall V3 locations, leaving two spots open for expansion without having to add new transformers or cabinets.
Trans-Canada 16 has less traffic then TC-1, so likely doesn't need any more than 6 stall V3 chargers either (at least to start with), which makes sense with the 8 stall locations for most of them - 6 as Tesla Superchargers and 2 as Universal chargers for funding eligibility.
There may be a few reasons Jasper has 8+3 rather than 6+2:
1. Due to the unique location in the tightly regulated national park, the approvals required, and the lot being on municipal lands, likely Tesla was concerned that starting with 6 now and trying to add 2 more to fill out the cabinets later might not get approved or at least will be difficult to approve later, so they may have wanted the maximized end count in their proposal so they don't have to come back later to add more.
2. Jasper is a tourist centre, so will, in addition to the through traffic on TC-16, will also have traffic through Icefields Parkway AB-93, and also tourists staying in town needing Supercharging for their visit, hence they may have anticipated more initial use than the rest of TC-16.
3. The remainder of the TC-16 locations are all on private lands and will likely be a lot easier to add on later when it merits expanding the number of Supercharger stalls. Also, they can add just the additional Supercharger stalls and not be required to add additional Universal stalls at that time.
Just my thoughts on this and why the 6+2 makes a lot of sense on most of the new sites.