Yes the final wash temp might well matter if it is a lot different from the dev/stop/fix temps. If you are developing to the Kodak times and it certainly looks as if you are using Kodak agitation and the negs look right exposure-wise then that only seems to leave 2 options:
1 The wash temp is the problem. It is a lot different from the other temps
2. Your definition of grain in a print is a lot different from other users and/or you have an ability to see grain which most of us do not have.
Option 2 would seem unlikely but cannot be entirely ruled out.However I'd check your wash temp and next time ensure that all temps are within about 1C of each other. The film should withstand a greater range but if this tight range does not solve the issue then you can at least rule out reticulation but I'd have no idea where you would then look for the solution.