I strongly doubt WABC's cash flow is that high. $6 million probably is a realistic guess if we're talking revenue.
I suspect their Broadcast Cash Flow is in the neighborhood of $2 million per year.
You are right in believing that there is no way that cash flow could have been $6 million. I've seen estimates of 2018 gross revenue of about $8 million. There is no way that they had an operating margin of 75%. 20% to 25% would be exceptionally good in this case, pre-sale.
So the cash flow on WABC in 2018 could have been in the $1.5 to $2 million range. And, going forward, much of the cash flow will be eliminated once the station is paying for its own management, back office, sales staff, rent and the likes now that WPLJ and Nash are gone. No cluster mates to share the overhead with.
I'd guess that the station is going to be losing money in its first period under new owners. No Cumulus / Westwood induced national sales, new studios to be constructed, and the full impact of a stand-alone management, sales, technical and back office staff.