Generally DDR/DDR2 kits do have the same first 3 numbers, this makes it easier for manufacturers to guarantee that it actually will work.
But if you notice, the recommended voltage for these kits is above the DDR standard (2.65v vs 2.5v), so they have been found to be tweakable (in this case by the manufacturer), lowering one or two of the subtimings like this will give you slightly better performance over the standard timings. Sorry, i don't have a tangible % improvement though.
So it is fine to have strange subtimings.
If you want to get a little bit more performance out of your memory then you could try lowering some of your subtimings yourself. Normally, this will require more voltage, and there will probably be one or two of the subtimings that wont want to move without making the RAM unstable.
My current RAM is running at
[email protected] (rated at
[email protected]). So you will probably have varying levels of success.
Dan