The maximum additional administrative fee that may be charged to employers in the public employees' retirement system, the public safety employees' retirement system, the school employees' retirement system, the teachers' retirement system, and the law enforcement officers' and firefighters' retirement system for any six-month period shall not exceed fifty percent of the standard administrative fee due for that six-month period. In instances where the standard administrative fee rate changes during the six-month period, the new standard administrative fee rate will be applied beginning with the month in which the new rate becomes effective. The maximum additional administrative fee that may be assessed is determined as follows:

(1) If the additional administrative fee as determined in accordance with WAC 415-115-080 is less than fifty percent of the standard administrative fee, the additional administrative fee is the maximum fee allowable.

(2) If the additional administrative fee as determined in accordance with WAC 415-115-080 is greater than or equal to fifty percent of the standard administrative fee, fifty percent of the standard administrative fee is the maximum fee allowable.