Systems, methods, and circuitries are provided for determining fallback behavior in a user equipment (UE) wireless communication device. The method includes signaling an enhanced processing time capability and fallback type to the wireless network, wherein the processing time capability includes respective numbers of transport blocks per slot the UE can process mapped to different respective specified numbers of serving cells. A number of configured serving cells that support the enhanced processing time capability is determined. The method includes determining, based on the number of configured serving cells, a maximum number of transport blocks per slot that will be communicated between the UE and the configured serving cells. A fallback behavior based on the determined maximum number of transport blocks per slot and the fallback type is determined.