Suppose you shoot a 40 lb @ 28  bow and you have a 29.5 inch draw. That means you're actually pulling about 45# bu exceeding the 28 inch draw by 1.5 inches. Now, suppose you shoot a bow exactly the same except it is a 45# bow at 29 inches. Will you feel a difference in the two bows regarding how easy or hard it is to pull to full draw? Would it be possible for them to feel the same?

Actually, increasing the draw length of a 40# bow 1 1/2 inches probably wouldn't raise the draw weight 5#.  More likely about 3#.  Your bow marked45#@29 inches would be about 43#@28 inches.  They're virtually the same bows and the draw would feel the same at the same draw length,i.e.,28 inches, or 29 inches, etc.  On one, the weight just happens to be marked at 28 inches, the other at 29 inches.

On 'most' bows its just a difference in markings.  However I believe some bowyers when they build a particular custom bow for a given draw may actually optimize that particular bow to pull for that length, so I would think the pounds/inch may vary a little vs a bow that's just for @28.  I don't think this level of customization is the norm, since bow length has more to do with it than anything and most bowyers offer different models or different lengths of model to cover different draw lengths, but some bowyers most surely need to know your draw to get the bow to perform to its max potential for you.

There are possibly numerous variables and the particular bowyer could provide the most reliable feedback.

If the bows are identical in all aspects with the exception of draw wt, i am not programmed well enough to consistantly differentiate between 2 to 3 pounds variations. If the bow has a draw wt well within my comfort range, and I could ascertain a slight difference, then I would most likely not detect a draw wt difference after a couple of shooting sessions.

Note: My shaft tuning has no problem detecting differnces.

As long as the bowyer did not optimize the bow to a specific draw length, you won't mention any difference.

It depends.  If the 40@28" bow is short, or has relatively short limbs on a longer riser, it might be at the limit of where the limbs operate efficiently and when pulled past 28" it begins to stack.  If so, then it definitely will feel a lot different from a bow that is designed for a 29.5" draw, even if they make the same poundage at that length.  It could pick up 5lbs in that last 1.5" distance and will feel harder to pull than the bow that goes smoothly to 29.5" and gains only a couple of pounds per inch in the last few inches.  If both bows are the same design, length, etc., and either bow will draw smoothly beyond your draw length, they will feel the same.