My opinion / Suggestion on the above after going through the above discussion:
First of all had the querist has data of attrition and reasons for the same, no information.
Seems he laid down a policy and seeking some sort of a ratification or indirect approval in this forum for his action.
I wish to say, any deduction from employee salary for retention will be a demotivating factor. Forget about retention, you may not attract unless your officer will be huge.
Secondly, is it legal to deduct in the name of retention. You are saying if he works for two years with you only repayment will be made. In case he has to leave for some reasons then what will happen! can your organization enrich unjustifiably?
Finally, as a HR person your strategy mush be towards motivating, encouraging and enticing employees towards your organization and by force or this kind of policies. This kind of policies give disastrous results in long run affecting organization in toto.
Dear Friend,
Please think in a positive way. your intention for retention is good but the actions not.