I don't know what the rationale was in establishing 40 points for a grand pass (the other point values were already established previously), but you are definitely getting all twisted up about nothing.
The only possible scenario in which it would matter if a grand pass was worth more points is in going for the 500 point club, 1,000 point club, etc.
I'm bored, so I'll break it down for you:
1) A dog must be a HRCH to enter the grand, so all dogs getting a grand pass have a minimum of 100 points prior to their grand pass.
2) GRHRCH requires 2 grand passes and 200 points. Since a dog must have 100 points to enter the grand then a dog with 2 grand passes would have a minimum of 180 points. I seriously doubt there has ever been a dog with 2 grand passes and less than 200 total points, but it could happen. The point remains that almost all dogs that earn their GRHRCH do so immediately upon their second grand pass because they are already sitting at 160+ points prior to the second grand pass.
3) You must have the 2 grand passes to get the GRHRCH, it doesn't matter if the dog has 5,000 points if they don't have the 2 grand passes they are not a GRHRCH. From that standpoint the grand pass (especially the second one) is absolutely priceless within the HRC program. There is NOTHING that can replace the second grand pass. No amount of 15 pt. Finished passes could ever eclipse the significance of the second grand pass.
4) Even if for some weird reason you never ran your dog in a Finished or Upland test after getting the HRCH and then got your 80 points for 2 grand passes, how much trouble would it be to go pass two more finished tests to surpass 200 points and get your GRHRCH title? Or one finished and one upland for same? Or two upland passes for same? No trouble at all.
If this is the only thing you have to complain about, life is good. Have a coke and a smile.