Recently,　C-30　coefficients　of　time-variable　gravity　field　models　from　GRACE　and　GRACE-Follow　On　(GRACE/GRACEFO)　are　reported　to　contain　larger　uncertainties　when　only　one　of　the　two　onboard　accelerometers　is　fully　functional,　which　mainly　concerns　the　GRACE-FO　period　and　the　final　stage　of　the　GRACE　period.　Using　these　problematic　coefficients　leads　to　incorrect　mass　change　(rate)　estimates,　especially　over　Antarctic　Ice-Sheet　(AIS),　and　a　replacement　with　those　from　satellite　laser　ranging　(SLR)　is　currently　recommended.　In　this　study,　we　aim　to　discuss　the　possibility　of　improving　the　C-30　coefficients　by　extending　the　GRACE-OBP　approach　that　has　previously　been　applied　to　the　estimation　of　geocenter　motion　and　variations　in　the　Earth＇s　dynamic　oblateness.　Such　an　approach　mainly　relies　on　GRACE/GRACE-FO　level　2　products　and　an　ocean　bottom　pressure　model,　and　it　produces　compatible　coefficients　with　the　GRACE/GRACE-FO　product　labeled　as　GSM.　With　a　numerical　experiment,　we　demonstrate　the　effectiveness　of　the　proposed　approach　and　identify　the　optimal　implementation　parameter　setup.　The　resulting　C-30　coefficient　time　series　is　generally　consistent　with　those　based　on　SLR　and　the　original　solutions　from　the　GRACE　dual-accelerometer　period,　but　with　differences　in　the　annual　amplitude　estimates.　Then,　we　obtain　C-30　coefficients　based　on　real　data　and　check　the　AIS　mass　change　time　series　with　and　without　replacing　the　original　ones　with　our　solution.　Our　C-30　solution　ensures　consistent　linear　trend　estimates　for　the　dual-and　single-accelerometer　periods.