Changing individual member's expirations

I have heard about using myadminphp for changing exp dates of manually added members; however, I stumbled across this process this afternoon and wanted to get feedback on whether or not this would be an alternative and much faster workaround.

1) Under the subscription “X”, the mode is set to “finite”

2) Under the Period it is set to 1 month and saved.

3) In the “All Members” select the individual members that have a month left on their annual membership before renewal. Choose “Subscription Move” and move them from “X” to “X”

4) For two month remaining members, set the Period to 2 months and again select those members with two months left and Move their subscription “X” to “X”

5) Repeat for each month – then leave at a 1 year subscription for all new renewals.

Will this cause problems? It seems infinitely faster and less dangerous than poking around in wp tables.