Sole proprietorship SIMPLE with employees

My husband is a sole proprietorship with two employees. We file a 1040 with a schedule C each year. Each paycheck, salary referrals are taken from the employees and submitted monthly with a 3% match for a simple IRA. For my husband to contribute, is it acceptable and correct to submit a 3% employer contribution of his schedule C profit by January 30 along with whatever personal amount up to the limits for that year?