Hi again, I've found another noncompliance, this time inside program area...
If the actual pause exceeds 2 s, the length of the start flag shall give the actual pause length. ImgBurn is writing a start flag beginning right at the track number change, instead of a subcode block later (the encoding of channel P is delayed by one subcoding block with respect to the encoding of channel Q), That wrongly increases the size of the flag by one sector.