Various embodiments provide methods implemented in a mobile communication device (e.g., a multi-RAT communication device) for maintaining at least one separate RGS value for each of a plurality of RATs operating on the mobile communication device. Specifically, a device processor on the mobile communication device (e.g., a crystal oscillator manager) may maintain a separate, up-to-date RGS value for each of the plurality of RATs and may associate each of the plurality of RATs with their respective RGS values. By keeping track of the plurality of RATs' respective RGS values, the device processor may ensure that an appropriate RGS value is used to facilitate each RAT's individual operations, such as acquisition/re-acquisition operations, sleep scheduling calculations, and handover/inter-RAT measurement operations. As a result, various embodiments may improve the performance of each RAT and the overall performance of the mobile communication device.