I read

"action A increases the value of utility function U"

to mean (1:) "the utility function U increases in value from action A". Did you mean (2:) "under utility function U, action A increases (expected) value"? Or am I missing some distinction in terminology?

The alternative meaning (2) leads to "should" (much like "ought") being dependent on the utility function used. Normativity might suggest that we all share views on utility that have fundamental similarities. In my mind at least, the usual controversy over whether utility functions (and derivative moral claims, i.e., "should"s and "ought"s) can be objectively true, remains.

Edit: formatting.