Whereas I adjust my time for whatever temperature I find the developer at. The A/C is a little overenthusiastic in my darkroom (might need to install a shutter over the exhaust fan to stop it collecting the lion's share of heat as well), so my temperature has been running below 20C, recently as low as 17C. All it costs me is any extra couple minutes tending the tank.
As usual, if you're happy with your results, then carry on.
I presume your concern about the wash step has to do with acid stop and/or fixer contracting the gelatin, making it harder to get the fixer out of it? Worth noting that all the washing instructions we have are also designed around acid stop and acid fix. Including the Ilford wash that lets me wash negatives archivally with just three tanks full of water. Ilford tested those instructions with their own products (films, developers, stop bath, and fixers), and they don't see an alkaline or neutral fixer.
Now, for prints, there could be a significant difference, but there the real problem is getting the fixer residue out of the paper itself -- the emulsion will wash clean in a few minutes, just like RC paper does after minimum fixing in rapid fixer. The rest of the time and effort in washing fiber based prints to archival standards is getting the thiosulfate out of the actual cellulose fibers.
