John,

There is a very small difference between 30 and 28.5 foot pounds - that difference is so slight that it is insignificant considering the pitch of the threads and the diameter of the bolts.

As you mentioned, Rotax has changed a number of their specs - all very minor - such as the spark plugs were 177 inch pounds (cold) once and now it is 180 inch pounds (cold) - again insignificant differences. Then there are the cylinder head nuts - once a specific torque was given and now they list a lower torque followed by a specific number of degrees rotation after - my guess is the final results are pretty similar.

If a person looks at the small differences as a percentage change rather than an absolute amount, it is easy to realize that other factors affecting torque are probably larger (wrench calibration, temperature of the parts, differences in condition of the thread surface.) We try to measure what we can to get as close as possible and then accept, by necessity, that absolute precision is a near impossibility.

In the end, we are all good.