If you assume an appellant's responsibility to post a bond or other surety instrument or demonstrate financial solvency under Sec. 1243.5, you:
(a) Must notify ONRR in writing at the address specified in Sec. 1243.200(a) that you are assuming the appellant's responsibility under this part;
(b) May not assert that you are not otherwise liable for royalties or other payments under 30 U.S.C. 1712(a), or any other theory, as a defense if ONRR calls your bond or requires you to pay based on your demonstration of financial solvency; and
(c) May end your voluntarily-assumed responsibility for posting a bond or other surety instrument only after the appellant under this part either:
(1) Pays or posts a bond or other surety instrument; or
(2) Demonstrates financial solvency.