This is a program for athletes who don't have a tonne of time but want to perform and improve. We've had guys and gals go top 5 in the AG off variations of this program so if you can follow it closely you should see good gains.
We throw the 2weeks on-1 week off out the window in this final block for several reasons.
1. You should have a big base leading into this block.
2. The last 2 weeks of it are already reduced volume.
3. There are plenty of rest days mixed in so you should get enough recovery.
Should you feel overly tired at some point i would take 3-4 days off or easy and try to get the weekend seesion. You can also back off the intensity/distance on a weekend session if needed.

I also encourage a Half IM event during this 10 week block. Week 3 (7 weeks to event) is ideal but week weeks 4 or 5 are also fine. Replace the big weekend session(s) with the race - don't try to make them up during the week. You can back the training off a little during the week and also the following week but try to do the hard session the following weekend if you are recovered enough.

The program uses Power and thresholds for the bike sessions. Using power is much more effective than HR, especially when riding intervals. Power meters are getting less and less expensive and if you look around for 2nd hand ones you can probably get one for a 3-400usd or euro, or a few thousand sek.

Use the resources within training peaks to get a good idea of your Thresholds (FTP, Run Pace Threshold, T-Pace for swimming) and you will get accurate training data you can use and build on for years.