Jim,
What were you hoping to achieve by appending "non standard" to your readback?
Were you perhaps trying to suggest that the controller had made an error? If so, you should have been more specific, or at least asked for confirmation.
Besides, FL330 is not a 'non-standard' flight level FL333 might be, but not FL330.
Possibly you think that evens for west and odds for east must be adhered to at all times? The semi-circular rule is only for the planning of cruising levels.
We had this sort of issue when we moved to RVSM. I remember the consternation shown by some pilots when they were allocated FL300 in the early months. A few just didn't seem to get it.
VL