Thistle, if it's an awkward fit with your coat, couldn't you just carry it to the office and put it on when you get there?

i love ponchos! have a few...wear them often. i wear as a coat even when its cold as i am usually always hot.

I kind the look when they're worn " on the go". Amazingly I saw some out& about this weekend in my small city and the wearers had great style.
It sounds like its very person- specific. I've so few occasions I can wear that I'm not determined enough to sub it for something else. To me they look best standing and walking, so perfect for fall strolling or errands or maybe sitting as on s mild football or barbecue event. It would bother me more sitting and arm- desk and getting to the Ladies'!
But others seem to find that no problem. An open front style might be less fussy as it becomes a version of cardigan and can be easily removed.
If you're pretty interested you could
order a couple and try around home for the " fussy factor" and mimic computer work. As above, perfect layering is hard and you could take it in a work tote- same principle as footwear. You could almost get that figured out even with one that isn't the perfect color, though styles and fabric weight are part of the equation.