Originally Posted by
A Squared
In FAA land, the specified phraseology for issuing a block clearance is: MAINTAIN BLOCK (altitude) THROUGH (altitude) So I use pretty much that "Maintaining Block 10,000 through 14,000" "IN the Block XXX-YYY" is common too. Agree that it's best not to report the specific altitude you're occupying at the time, and It could lead to misunderstanding if the block altitude clearance is forgotten or not passed on to a subsequent controller.
For ATC your current level while in a block is irrelevant. They need to know the block levels as you have full authority to climb and descend as you please within it with no requirement to inform them. They need to keep all other traffic clear of the entire block.