Update or insert into T521B

Hello,

I would like to know is it possible to update T521B or to insert into T521B directly through ABAP code, using function module or something similar? Just to explain, I know that I can directly update or insert rows into table, but I am not sure that I won't mess up things in T521B by doing DML statements directly. I have to insert about 10.000 rows and I need to do it in the most efficient way.

I would greatly appreciate any advice.