In its cost benefit analysis, the regulator said it expects one-off compliance costs to range between £42m and £67m, on the original MMR proposals.
The regulator admitted it had underestimated the compliance costs of removing the non-advised sales process.
The FSA said one-off costs of the advice proposals are likely to increase from its previous estimate of £0.8m to £2.8m. It expects ongoing compliance costs on its advice proposals to increase from £1m to £3m.
It said it had revised its estimate to take into account the fact that some lenders have a much larger percentage of non-advised sales at present and may need to recruit additional staff.