Hi Lullaby and welcome
I am reasonably new to IUI myself and am finding that a lot of specialists are different in their methods etc.
I have had one round of IUI with Puregon and Pregnyl which was a BFN but I was never asked to get blood tests done to check levels so I don't understand that. But I was on 75iu Puregon as well and this time they have up'd my dosage to 100iu.
All they did with me was I took about 5 injections with the Puregon pen, i went in and had the ultrasound to check follicles, went home had an injection of Pregnyl then after a few days went back in to have the insemination, then 2 booster Pregnyl injections on day 4 and 8 after that. I think was how it went. Sounds a bit different to you - interesting!
I wouldnt stress over it too much if you can - just hope for the best. You will get there.

I'm about to start round 2.
Fingers crossed for the both of us. Best of luck.