The pole top allowance modifier is applied to wind load on pole in tipload calculation. In version 6 this value is used in the working stress tipload module but not in the limit state module. In version 7 it is used for all tipload calculations.
The default value in version 6 is 1.1 and in version 7 it is 1.
For limit state calculations the value of 1 should be used unless specified otherwise by the utility. For example in the Ausgrid design manual NS220 section 12.4 you will find the statement “For distribution applications, windage on crossarms, insulators and other fittings is often allowed for by applying a multiplier of, say 1.1, rather than by detailed calculation.”