Low impact, confusing comment/docs since the lastAccruedBlock is either wrongly implemented or wrongly named.
Take a look at PrimeLiquidityProvider.sol#L22-L24:
As seen, lastAccruedBlock currently claims to be the rate at which a token is distributed to the prime contract, but this is wrong since this mapping actuallly holds value for the last block an accrual was made for an address.
Fix the comments around the lastAccruedBlock mapping or change the name itself.
