This topic, IMO, is closely related to the "what would I do differently thread" where 90 percent of the answers are bill more.
I tell a client, if I need to use our research center, the fee is $125 plus my hourly rate as I "pay per use".
Any tax problem that you can't solve or find using the tremendous resources on the internet need be billed.
I no longer have a research program (don't tell the clients). I can't think of a complex problem I couldn't find guidance on Google. Whether it's Cornell University law source, Tax advisor articles etc. I have narrowed my clients to S Corps and Individuals , a few LLC's. If I have a tough situation, after using the "net" I also have told the client I want a 2nd opinion and it would cost $X. I did that twice last year. I wrote a larger form a check and billed the client.
So I think it is more a tax management issue.. why are we doing clients where we need the same research program as PWC or Deloitte?