I have noticed an ever increasing problem where the leasing agency has computed less mineral acres than you think that you own.
My standard operating procedure is to require the leasing company to provide a runsheet, along with a mineral breakdown for my client's interest on a tract basis and a plat shaded on a tract basis that ties into the mineral breakdown.
Many companies knee jerk reaction is that this is their work product and they will not give it. I was trained that the land business is one of building good relationships. I would never refuse a reasonable landowner for that request. Others will disagree, but I have been very successful on the company side treating mineral owners better than I would expect for myself.
If the oil company is unable to arrive at a net acreage that you can confirm, what I have done in the past is to have a side letter agreement wherein if a later examination of title discloses additional net acres, then the company is bound to pay additional bonus based on the new net acreage amount. Now, I have begun to include words to accomplish the same in my proprietary lease form.
To summarize:
1. Make the oil company prove up their title into you.
2. Have the oil company furnish you with a runsheet (history of title) as to your interest.
3. Protect yourself if additional net acres are proved under the lease and make sure that you are compensated for those additional net acres.