This is for D. M. Stevens, with warmest wishes.
Winry's contract forbids her to moonlight. The company, claiming the rights to whatever she invents while in its employ, on or off the clock, cannot disclaim liability for any maintenance or installation she does in her free time, either. So Winry keeps her best inspirations in her head and disappoints most clients by refusing to tinker outside the office. Sorry; I need this job ...
Ed's the exception, of course, taking her oh-so-casual suggestions to Riesenbuhl for Granny to implement and trysting with her in discreet hotels for adjustments. It's like we're having an affair, she teases, grinning as he blushes.