<<Disclaimer: Verify this information before applying it to your situation.>>
 
In answer as to why your bread is still falling, it may be you have too much
yeast.  Try to reduce the amount of yeast by 1/2 teaspooon and see if that
helps.  If that does not you may still have too much moisture for the humidity
in you house.  Winter does not cause as much trouble with humidity and bread
results as spring and summer.  I hope this helps.
 
Ruth E. Smith     Barrington, Il.