I'd tell you, but that would be telling
No. The separate cut off for graduates applying to the A100 degree is for two reasons:
1) You cannot compare graduates to school leavers on the basis of the UCAS tariff. Most graduate applicants have fairly average A levels, and A*s did not exist in our day. It would be unfair.
2) You cannot compare graduates to other graduates on the basis of university results. Different universities have different weighting systems, modules etc. The minimum academic higher education entry requirement is a 2:1. It would be unfair to reject one candidate because they got 64% and accept another because they got 66% as these scores are not the same as A level UMSs. Again, it would be unfair.
So, from the above you can see that the only standardised method of discriminating between graduates is on the basis of UKCAT scores. That's why we're considered separately to school leavers. Actually until this year, all applicants to A100 (graduate or otherwise) were picked for interview on the basis of their UKCAT scores. Last year, the universal cut off (for grads and school leavers) was 642.5.
The university will (with some justification) assume that graduates will have done their research and realised the financial implications of applying to the A100 degree for 2012 entry. If people are willing to shell out the money (and believe me, I know people who are planning to remortgage their homes to do so) then the university won't care, so long as they get their fees paid. However, you're right, the number of graduates applying to A100 this year may well drop, though this won't be due to an alteration in BL policy, but due to the government's idiotic fees increase.