Dear Pankaj, the clarification sought by the labor department on the variance of the wages paid to categories of workmen is justified, which is evident from your clarification. As per you, some skilled category workmen are paid under the minimum rate of wages of the USK category, whereas they fall under the SK (Driver, Casual Operators, Office Boy, Supervisors & Guesthouse Cook) category. You cannot call it a substantial variation but rather a serious violation. This can be treated as a willful violation of minimum wages. As an employer willfully (a) pays to any employee less than the minimum rates of wages fixed for that employee's class of work or less than the amount due to him under the provisions of this Act or (b) contravenes any rule or order made under section 13; shall be punishable...
If your rate of payment is equal to or more than the original skill category to which the workmen belong, then the category maintained in the register is not that serious and can be said to have happened due to a clerical mistake. But if the rate of wages paid to those workmen is less, it is to be considered a violation. In this regard, you have to rectify your register as per the skill and pay the variation amount from the date their name was borne in the muster roll till date.