DTA accrual for mobile participants

This week I came across a very interesting request/question, and I must admit, it's the first time I hear this.
This auditors have requested the DTA accrual to follow the expense mobility accrual. So if part of the expense is accrued in CC 100 and stays in CC 100, the portion of the DTA that was accrued for the amount of time the grant expense was allocated to CC 100 must remain allocated to that cost center.
At the time of exercise/release, the actual benefit has to be pro-rated among the various cost centers based on the same time schedule the participant was employed in each of the cost centers, which should match with the time where the original accrual was booked.
While I can see the argument of doing this, in particular if there is no sufficient APIC Pool and when the stock price is in decline any additional tax expense would be proportionally charged to the cost center where the benefit was originally booked, I'm also a little confused.
For once under ASC 718, the actual gain at exercise/release never matches the expense and a difference is inevitable, but the entire overall tax accrual and benefit is rolled up to the corporate level. Also, the corporate tax rate used to calculate the actual tax benefit might not be the same tax rate that was originally used to book the accrual.
As anyone else come across any similar request, or heard about any guidelines on this?
Thank you in advance for any information you can provide.