I’m trying to better understand how to credit service using the elapsed time method on a plan year basis. I want to avoid crediting each employee on their hire date for simplicity reasons. Is there more than one way to accomplish this?

In a word, no. The regulations clearly state it must be on an employment year basis.

On trick, if you allow NO credit prior to the effective date of the plan, and the effective date is the first day of the plan year, at least your initial participants are on a plan year basis.