Change expenditure item date upon transaction import

We want to burden based on accounting date, not expenditure item date.  One of the proposed ideas is to update the expenditure item date upon transaction import to reflect the accounting date and storing the expenditure item date in a flexfield.

I don't know if I like that idea since the expenditure item date is used so widely in the application, but wondered if there was anyone out there who had done something similar?   And that maybe you'd share your opinion?

Thanks!