What if you suspect your attorney is holding back more of your settlement than they quoted to you?

The simple thing to do is to demand a copy of the settlement check.  This will tell you how much was paid.  The second thing is to demand a breakout of how the proceeds were distributed.  This should be much faster than dealing with the Maryland Attorney Grievance Commission (the "Commission"), espcially if you tell the attorney if a breakout is not provided withing 10 days you intend to file the grievance.  This proclamation will get results faster than anything else.

Also licensed and practicing in Maryland.

First, contact your state Bar Association: many state bar associations will help resolve monetary disputes between attorneys and their clients. If that does not satisfactorily resolve the situation, you could sue your attorney to recover any amounts which he should have turned over to you but did not; an attorney is only entitled to keep that amount of the settlement which you had, in engaging his representation, specifically agreed to pay him. The agreement (whether written or oral/verbal) between you and your attorney as to his representation of you is as enforceable as any other contract.