i don't understand what you want.
the data sheets i have, doesn't say a thing about leap years in memory location 05.

all that i can see is that memory location 05 has 6 bits for the day (2 for the ten days, and 4 for the unit days (BCD)

and bit 7 and 6 are for the year. (0 to 3 binairy).

can you tell me what you ment with your reply, leon??