[Translator Reform] Core Grids: Why give a "discount" on points to fill-in FM translators carrying an AM station but not to fill-in FM translators carrying an FM station?

NOTE: This answer relates to a rule proposed by REC and does not reflect current regulations in effect:

REC considers FM translators used to rebroadcast Class C and D AM broadcast stations to be a "community need" under Section 5(2) of the LCRA and we feel that these translators deserve some consideration as they are more likely to serve their local community than a translator carrying an FM signal or HD subchannel in an urban area. To assure simplicity in the process, we are also giving the discount to FM translators carrying Class A and B AM stations.