R12 implementation - should we use 11i account generator or SLA

My client are partaking in R12 re-implementation. Currently they charge depreciation to cost centre. With R12 they still want to charge depreciaton at cost centre level but also want to do the same for accumulate depreciation and asset addition. Each asset assigned and expense account for depreciation and I was thinking of using the expense account cost centre segment as the source for the value for generating the CC segment for accumulated depreciation and asset. Are we better off customising the account generator or using the new functionality in SLA be creating a new accounting method with derivation rules for