At the Monotype website
www.fonts.com/Legal/MI-EULA.htm
we read in section 15 of the Monotype EULA:
"You agree not to adapt, modify, alter, translate, convert, or otherwise change the Font Software..."
After having bought a TrueType font at this website, do you commit an infringement, if you convert this TTF font to a PostScript Type 1 font?