Watch what your ball is doing through the pins.  If right handed and leaving 7s there's definitely some entry angle issues.  10s, are they ringing or flat?  Is your ball deflecting out through the 9 pin towards the 10? This is the issue you want to look at,  not the ball weight.

On a pure physics basis 15 will defkect more than 16 which can reduce carry.  However most of us increased our rev rate when we dropped down in weight.  Also, the added speed achieved helps to keep the rotational energy from burning off too early.  However, everyone is slightly different.  If you arent gaining in speed and revs, you will see more flat 10a

Not sure I saw any difference on 8s snd 9s from dropping down.  So many other variables on corners that I have never been able to definitively say there is s difference.  My gut feel is that over a broad range of conditions carry between the weights has been a wash.

There are so many variables that will have an effect on pin carry that the physics behind it can get quite complex. Almost everything you can think of will have an effect on pin carry. These variables include, but are not limited to:
 
Ball weight
Pocket entry angle
Pin weight
Ball speed (both, linear and angular speeds)-- both are important!
Pin speed ( which is determined by the 2 ball speeds AND the what's called the "Coefficient of restitution" of the ball pins,and sideboards). 
The ball's momentum [ both linear and angular, which is equal to the ball's weight TIMES speed (for linear momentum)].
The amount of TIME the ball is in contact with the pins (it's called "impulse")-- the one quantity that is often overlooked, but it is an extremely important factor.
The amount of friction between the ball and the pin deck.

The above factors are largely affected by the bowler's release style. Different release styles will affect all of the above variables to widely different degrees.

However in in GENERAL, a HEAVIER ball will knock down more pins than will a lighter ball. Increased entry angle can make up for some of what is lost when going to a lighter ball, but there is a limit to this advantage. That limit will depend in large part on the other factors listed above. 

In the end, it is much easier to let your eyes be your guide as to what ball weight works best for you where it comes to creating optimal pin carry ( I am not taking physical limitations into consideration).

 I am a speed-dominant stroker. As such, I have tried different ball weights
(from 14# to 16#). For me, the jury has long been in on what ball weight generally knocks down more pins for my particular style--- 16#.

You are incorrect when you state a 16lb will deflect less than any other weight...it’s dependent on how it loses its speed plus rotation...if speed and rev rate does not match up in regards to environment it’ll deflect more...simply weighing more does not constitute a perceived higher hitting percentage

Read my lips.  All other things breing equal means primarily speed, axis rotation and rev rate.  When those elements are the same the heavier object will always deflect less when striking another object at an oblique amgle.  The point is that these elements ate seldom equal when a person drops down in weight thriwing a ball. 

Sorry, I dont usually do that.   Just a little crotchety this week.  As  for the rest of  my posts lacking in substance, I hope others dont feel that way.