Add dynamic to messa di voce?

Can a dynamic mark be retroactively added to the middle of a messa di voce (< >)?

I tried, and it seems not. I understand why a messa di voce should be treated as a single expression, but it would be helpful to be able to add a dynamic at its apex (which I suppose would break it up). Thanks.

I thought MdiV was more like a slight swell within the current dynamic, i.e. not the same as a crescendo hairpin followed by a decresc. hairpin. D. seems to make the same distinction…?

I know, I realize adding a dynamic in the middle would change it. Just a thought.