Yeah, people are just incapable of reading once again.
You can do 45/15 as a regular subT session where you mostly stick to a single pace, probably about 10k pace for most people -- that's not much different from 400/30 or 60/30 and, at least for me, actually easier on the legs for some reason.
Or you can do it as an X-factor, start around 10k and finish around 3k pace, which probably is fairly close to a parkrun in terms of load.
SubT + 5-10x45/15 he mostly suggests for FT people, which makes sense to me, and long plus 5-10x45/15 to mimick the feel of a marathon, which is more or less a regular fast finish run.
As a regular subT session it doesn't feel all that interesting to me but it probably gives you a slightly better bang for the buck then, say, an 8x3 session, if you're really struggling for time, as it keeps HR high throughout. If you look at HR afterwards it almost looks a bit like a progression run or an incredibly long subT interval where always hovers right below LT2HR for the last 10 minutes or so.
As a fast X-factor session it's a lot of fun and definitely feels better than a 6x1k at 5k pace or something along those lines.