Thought you may have been Dutch because I know a particular company was perhaps going to change their SOPS
The sensible thing would surely be to implement/execute the change on the MCP then have the PM (when back on freq) confirm with ATC what the cleared level was?
Stats tell me that by far and away the biggest cause of Level Busts (in this part of the world anyway) is correct readback followed by incorrect action- i.e. Between the readback and verification of the MCP something changes.
The use of 'expect' (when used) has a part to play, and this is being addressed.
Pilot expectations also play a part (eg. check in on freq maintaining SID altitude, asked to squawk ident, then another flight is given climb, but the first flight answers
).