modulo and frame number in mframe_sched.c

Hi.

In "struct mframe_sched_item" in target/firmware/layer1/mframe_sched.c both 'modulo' and 'frame_nr' defined as uint16_t. This seems like big space waste considering tight memory environment we're working in.

On irc it was suggested that the reason for this is either data alignment or safety concerns.

Does structure alignment matters in this case? If so - how exactly? Is it possible for 'modulo' to be bigger than 255? Is it possible for 'frame_nr' to be bigger than 255?