This is a new idea to me, I usually do Autumn pruning to stop bushes rocking in strong winds, the roots don't like it, but leave three buds past my final prune to allow for Winter die back, then make the final prune in the Spring. Does it get very cold in Milwaukee? Your solution sounds like a good one, firming the bush and giving protection from frost, shame about the fungal negative aspect. On a purely hypothetical basis it sounds as though you have it right though, fungi will be much less active the colder it gets.