no, it's not some terrible thing that makes it an inaccurate rom infact, i'm not sure if the same problem happens on the orriginal machine
it seems that BW(anthing other than A) is immposible to enter for initials
you see, although my initials are not BWS(long story, completely unrelated) , that is what i enter for my highscores and on three different computers using two versions of mame32 i and friends have gotten the same result
entering the B... no problem then the W, WA... WA? no, BWA, what the heck that's not what i wanted to enter, oh well i guess as long as everyone knows the top score is mine i'll get over it