Considering that, perhaps, the majority of pilots reading this do not have English as their first language I think they should make text as simple as possible and avoid questions. (a comment I made to some previous airlines where many crew notices needed 3 or 4 readings, and even then.......?)
The first sentence is an instruction to the crew. Maintain last assigned level by ATC. Clear. It doesn't matter if this is above the 'level flight chart segment' or not.
The 2nd sentence is an instruction to ATC. If they want the crew to maintain a level above the 'level flight chart segment' they have to instruct the crew. i.e. back up the SOP of the 1st sentence.
I suppose it could be called belt & braces; but when reading both sentences it make me wonder if I misunderstood the first one. That seemed as clear as could be.
Am I missing something?