Discount rate to discount FRA benefit to FRA maturity

Hi there CFA curriculumn uses a LIBOR only discount rate to discount the FRA benefit to FRA maturity Schweser uses LIBOR+spread discount rate to discount the FRA benefit to FRA maturity which one is correct? (PS: Both however use the riskfree rate to discount the FRA benefit from FRA Maturity to a time before that) Help will be greatly appreciated