Wage type split during mid-pay period is accumulated in OT

I am new to payroll processing and I would like to understand why split reoccurring payments are being processed the way they are. I have a scenario where a reoccurring wage type changes mid-pay period from 2% to 4%. It seems that when “P0014 Z011 GEN NOAB“ is processed, it accumulates the value in the OT to be 6%. What causes the accumulation to happen? Is it possible to store the two WT values separately in the OT for further processing?

Thanks in advance for your responses!