I don't find a  consistent  pronunciation of the political office "Comptroller".  When I lived in New York, the office-holder pronounced it "Con-troller" (which the dictionary lists as the primary choice), but here in Illinois, it is pronounced "Comp-troller".  I'm sure either is acceptable, but shouldn't such an important office be pronounced in a consistent way?
This is an interesting case of spelling and pronunciation reflecting two different senses of the word's origin. Â The mpt doesn't really belong there; the word comes simply from control. Â
But control has changed its meaning over the years. Â It comes from contra + rotulus. Â The rotulus was a scroll, and contra-rotulus referred to an early form of double-entry bookkeeping. Â Balancing one scroll of numbers against another. Â
In European languages, controlling still means checking, auditing, proofreading. Â Â In English it has come to mean dominating or taking charge.
In companies or governments that have a Comptroller, the job retains the old European sense of auditing, not the modern English sense of taking charge. Â So the spelling of the job changed at some point, with a false back-formed etymology from French compt as in compute, which became count in English.
The comptroller's job is related to computing or counting rather than dominating, so his title took on a spelling related to counting or computing.
Thus you can pronounce it either way, but you're favoring one sense of the word by your choice.
In writing though , 'comptroller' is a word that is not interchangeable with any others. Some dictionaries say it is a variant of 'controller' - wrong. Or is it?