No. The prolactin is potentially a good indicator that e2 is in fact too high. E2 can, amongst other permissive actions towards increased prolactin secretion, directly stimulate lactotropes in the anterior pituitary to stimulate prolactin.
However, deca is also in the picture, which also has a positive relationship with prolactin release.
Nonetheless, no doubt both factors are most likely contributing towards increased prolactin levels, however amongst the two, I'd speculate that e2 > 100 pgml is the bigger offender.
Adding to the complexity, you have 400 mg's of mast in your system, and the high e2 levels don't represent the actual estrogenicity as mast is anti estrogenic.
Nonetheless, due to various reasons which I'm not goin in to now, you don't want high e2 levels when you are on a progestin such as deca, so yes, lower your e2 levels. If prolactin doesn't drop by then (which I doubt), then consider some soft actions (not caber or prami) at lowering it a bit - it's not that high.