Iron lofts have gotten stronger, so, the labels for hybrids have changed to go along with it. A 3h use to be 21 deg., now a 3h is 19 deg. You should ignore the ?h label, and, get the hybrid that matches your current hybrid's specs - loft and length.

The 915 may have been labeled 5H - 27, but the newer models in both fairways and hybrids only list the (RH) loft at A1. The T series irons for a 5 iron run from 27 degrees for the T100 to 20 degrees for the T400 with additional lofts of 25, 24, and 23 degrees. Which 5 iron should the hybrid be based on? So finding a demo or Titleist Thursday you would need to compare a hybrid to your lowest lofted iron you can hit and gap the distance accordingly by loft and not looking for a X Hybrid to replace your X Iron.

As an aside, using lofts and not numbers dispels the nomenclature to refer to a 13.5 FW as a strong 3W or a 16.5 as a weak 3W or a 4W. (3W being a traditional 15 degrees). With lofts all over the place when comparing to other OEMs, the use of 5 iron means nothing other than the next iron up from 6 iron in the same set.

And with the complexity/simplicity of the Sure fit hosel, you can adjust Loft up or down and lie. I just put a TS 2 21 degree hybrid in my bag and it rocks!!! I will replace my 25 degree 818 soon.

This should help

Specifications
Model Loft Lie Length
1 Hybrid 17° 57.25° 41.00"
2 Hybrid 19° 57.50° 40.50"
3 Hybrid 21° 58.00° 40.00"
4 Hybrid 23° 58.50° 39.50"
5 Hybrid 25° 59.00° 39.00"
6 Hybrid 27° 59.50° 38.50"