What did your fitter recommend? The new T series irons have shown advanced technology has helped a lot of golfers. I am 77 am still hitting steel shafts. Have tried graphite but there are a lot of lite shafts that work as well. Trust the numbers from Trackman and recommendations from an experienced fitter.

Are you talking about reshafting your existing heads (AP2)? Do you recall which metric or metrics that was/were influential in producing the extra 10 yds? Assuming you gained more swing speed, that could be expected since the graphite shafts a lighter than the TT AMTs. You might be able to transfer this higher swing speed by just reshafting your existing clubs. Again, if there was some other metric that produced the extra distance, then reshafting may not result in the same distance gains. A good fitter should be able to do a deeper dive and advise you properly.

Did you notice the difference of loft?
For a 6 iron in Ap2 it is 30 deg. In T200 it is 27 deg.
The T200 should hit further with the TT Amt also.

Before taking my decision, I would like to test ap2 with the graphite shaft on a6 iron to insure that this the launch, feel and dispersion that I am looking for.

It is not always easy to pass from steel to graphite for irons.

Good luck on your research,

If you found 10 yards, there you go. If the forgiveness and dispersion is better (I would imagine it is) then that backs up your answer. I'd say invest. Your 65 years young and have plenty of golf left, so if you have the means, go for it.

The 718 irons are 6 years and 3 generations back. The Gen 3 T200 irons are a significant improvement over prior T200 irons.
Since you were still in your 50’s when your irons came out, and 6 years from now you will be in your 70’s. The T200 is more forgiving than the AP2/T100. The Titleist fitters can also recommend what your set should include for consistent gapping with a potential to use a T350 as your longest iron(s).
Up to you now or later, but none of us have beaten Father Time. At some point you’ll need an upgrade.