I reckon your upper cowl wash 'chipping' is too extreme. I get where you're going with that whole idea... high traffic area for ground crews etc etc but from a distance, I think it just stands out way too much.
Softening it out a little and making a little less of a stark contrast would have a more authentic effect, I think.
Even if that much paint had come off in real life the 'digitalness' of our representations exagerates a lot of details, I think. As we only have the ability to work with 1 pixel lines, by scale that is a huge line. Try dropping off the amount that your enginge bay covers stand out a little... Half way between what you've got going there and what people usually do would be a more realistic interpretation in my opinion.
The underside of the fuselage would probably be showing a little more dirt too.... not even dirt necessarily, perhaps watermarks from snow or something... Snow and slush.... low undercarriage and prop spray would have the fueslage pretty dirty, not just wheel-track area spray.
That will depend on what part of winter you want to portray, though, I suppose. Early or late = mud slush filth.... middle of winter would see far less I suppose... thick snow and ice for runways. That would lend itself to 'watermarks' though, I'd say.
