Yes, expensing IDC should lower your taxes as you are getting a larger deduction because you have larger income (although may be sheltered by capital losses)by way of the 1231 gain.
However, it is my understanding that this becomes a binding election for all your MLP's for all future years (Pub. 535, Business Expenses,page 20). This could bring into play AMT. This should not be a problem unless IDC exceeds 40% of AMT taxable income in a future year. This, of course, depends on your income and how extensive your investments are in MLP's exploring and developing oil and gas. Pipeline MLP's, generally, don't have IDC.
It appears that Obama budget is trying to take away expensing of IDC, so that option may be taken away in future years along with percentage depletion. Just what we need - less incentives to find more oil!