Crescendo and decrescendo (2)

Further to my post on the same subject:

It's clear in the example below that < and > don't work over a SINGLE note. (First 3 bars) So, I tried a workaround: create a further note! In the 4th bar, I put a 32th note, but the < still it does not work. However, the > works fine and the note in the 6th bar continues as 'pp'.
In the 7th bar, it also does not <... And the 8th bar is just 'ff'.

Any comments here?