but on the other hand so does the Allison book state that Kerosene is an accepted fuel
Edd, would like to see the verbatim quote and the reference manual. Also note that it is the aircraft manufacturer who decides what is acceptable, not the engine manufacturer (though of course they do talk to each other) and requirements will be so quoted in the flight manual. If its not in the flight manual its no, no, despite what you may find in other documents.
You need to be very careful of using the term kerosene because the term can cover a wide range of products. The following are the fuel specs as called for in one particular helicopters flight manual.
You will note that #3 calls for Kerosene. But the requirement is for it to meet the specifications called out in ASTM-D-1655 JetA (Standard Specification for Aviation Turbine Fuels). A drum of the stuff from Wal-mart made for your camping equipment will not comply.
Fuels are required to meet certain specs, and even then you can run into trouble, as one New Zealand airline found out. The particular batch of fuel lacked the necessary lubricity properties, and the FCUs were giving up the ghost, resulting in engine failures. Was found the fuel specs did not adequately address lubricity issues.