Couple of concerns ..
(a) As long as you're not below that acc alt, you're pretty much safe.
Point is that you can't relax until you are above the critical obstacle(s). Even then, you must be sure that your relaxation isn't going to bring additional obstacles into critical play. ie fly the profile as published.
(b) Minimum flap retraction altitudes are just that...minimum altitude. Nothing prevents you from retracting them at a later time.
The only minimum, as such, is the 400 ft requirement. Otherwise, the escape is predicated on the sums. Unless you know that you are above all relevant obstacles (which should be addressed by some explicit means in the procedure) extending the second segment might compromise you a little as the gradients (and, hence, third segment distance) are affected.