I have tuned my share of hybrids, some are dissapointing and some not so. But when you have to retard the timing so much that the timing map doesn't look any where near what a 205 or 257 map is you can be certain that the combustion efficiency just isn't quite there. Timing also plays a large roll in telling how a motor behaving. Any time the timing can be advanced toward TDC you stand a good change to make more Hp, but by far the biggest gain is that you have a larger safety margin against detonation. Better ignition timing is a sign of more efficient / controlled combustion. This efficient combustion goes hand in hand with better fuel economy, more knock control, and better driveability. Since most hybrids struggle with detonation I feel that being able to run better timing is a big sign that the motor will not have to deal with detonation issues as much at any given power level.