By taking the MEPL + MEIR route you will have a minimum of 21 hours on the multi. By taking the SEIR, MEPL, SEIR-MEIR conversion route you will have 11 hours on the multi. To be honest the MEIR skills test is hard enough with only 21 hours multi experience and most students opt to do a few extra hours on the multi before test.
By opting for the SEIR conversion route you may think that you will be saving money, but in the long run you will probably wish to do more multi flying which will add to the cost.