.4 - Problem is our SOPs are already designed around "breaking" your 160 to 14 (1410'?). Gear now goes down latest at 1680', and that will govern when you slow from 160K. Add any "comfort factor" in (as some do) and we are defeating your aim.
Why? The airlines are getting more and more sophisticated software in the QARs, tighter SOPs, and we got more b*llockings in fleet magazines and by phone by not adhering e.g. to stable by 1080' - this needs you to slow to Final Speed, and have the power up - which as you say, can be v difficult in a 319 (since there is so much speed to lose).
A letter to the BA office might help, since there are all sorts of rumours about what is acceptable to comply with "160 to 4" e.g. "there's a 10K tolerance" etc. I am not that happy disregarding an instruction on every occasion, so some clarity / agreement would be welcome!