Kyocera, PRESCRIBE, font settings, problem

[Kir]

Hi!

We have a system that prints ASCII-based reports to Kyocera printer
using Prescribe commands to format a page. I've tried to bracket
certain fields into
!R! FSET 5b; EXIT; ... !R! FSET 0b; EXIT;
or
!R! FSET 1s; EXIT; ... !R! FSET 0s; EXIT;
to get these fields as bold and italic respectively. Aside of desired
effect, though, these fields look at paper as half-height and
demi-light (so the field in "bold" can be called so only in a way of
wishful thinking). What I'm doing wrong?

Thanks in advance.