S-rank multiple weapons problem

[Belf]

I'm able to get my characters to initially s-rank in all of their usable weapon types, but after awhile the multiple s-ranks disappear and only one remains with the other weapon ranks changing to a full A rank. I don't know why this autocorrection is happening, and I'm wondering if there is a known way to permanently make all weapon types s-rank for a character/class?

Note: What I did was change the character's starting weapon ranks to all S's. Like i said before, it worked at first, but a few chapters later the game had auto corrected itself somehow.

[Mage Knight 404]

The problem here is that you changed the base weapon ranks for the character when you should be changing it for the class. If a class has a base weapon rank of S in multiple areas(and only S, any lower and it won't work I'm pretty sure), then the unit can get multiple S ranks.

A friendly note, though. Promoting to a class with base S in weapons will likely automatically jump the unit's existing weapon rank to S as well, IIRC. Just in case you wish to have the player still wanna work for it the hard way, you should only reserve this for classes that are already promoted or can't promote.