[Ifeffit] XANES relative peak energies

Hi everyone, I am using FEFF to calculate XANES spectra for calcium carbonates, and I am wondering how precisely I should expect the relative peak energies should be consistent with experiments. Is there anything I can do within FEFF to shift peaks relative to each other or to stretch/compress the entire spectrum? I've tried increasing l_fms (or lmax2), which helps some but not enough. Thank you! Ross DeVol University of Wisconsin-Madison