Failed "55% DCAP" test

So, IN January of 2018, someone sends 2017 data and asks you to do DCAP testing. They pass the "5% owner" test, but fail the "55% DCAP test."

Lets us just suppose that the HC average benefit amount was $1,000, and the NHC average was $300.

I'm being told that as long as it is "corrected" by the time the W-2's are done, that instead of the entire HC amount being considered taxable income, you can just count the excess over what "would" have passed.

So, for example with a $300 NHC average, if the HC average had been $545 (I'm rounding here) then it "would" have passed, and therefore the HC taxation on the DCAP will only be amounts in excess of $545.

Is this approach "blessed" anywhere in IRS guidance? I don't find it anywhere, but I'm not a cafeteria plan expert. Do people just do it this way, even if not officially sanctioned by the IRS?