Facts - few to none are going to get an account transcript even if we ask them nicely.

In my office whenever we have a difference of expected stimulus to actual stimulus we send out with the return on a separate page (neon yellow) a memo explaining (a) the situation, (b) telling them the extra recovery included in their return,(c) point to the Recovery Rebate Worksheet we are including in the return, (d) informing the client that should the IRS state the Stimulus 2 is "in the mail" or whatever other issue, there may be an adjustment to the return.  We just don't know how they will do this: adjust the refund, send a letter, send a CP2000 or whatever notice, etc.  

By being upfront the client knows we did our best to handle this bungled situation.