Tailors - does fixing sleeve pitch provide any compensation for low armscyes?

[NukeMeSlowly]

Just picked up a vintage leather 3/4 length coat - nice thick, tough leather.
Overall the fit is very good but it has somewhat largish/low arm holes so my arm movement is a bit restricted (especially with the coat buttoned up).

The sleeve pitch is also more than a bit off. Just wondering, will having this corrected provide any relief from the effects of the low armscyes?
Since thick leather is much less stretchy/forgiving than wool, I would imagine that if the sleeve pitch is retrofitted to my body's particular slant there would be some improvement in my freedom of arm movement.

Is there anything to my conjecture or am I deluding myself?

 

[a tailor]

if the coat is very square shouldered, and you are very sloping shouldered there may be some help.
if the difference is one at least inch or more.