When you're already locked in on a rate & the rate drops, can I get that lower rate? 10days to close

You'll have to check with your lender as that depends on their specific policy. Some offer float downs, some do not. Likewise, some are free and some are not. Your rate lock assured you that the rate you agreed upon would not change. It's a shame you might be unable to take advantage of a lower rate but that's generally a difference of a few dollars per month. It's worse when the rate goes up and you are not locked as that can and does disqualify some from financing due to the slightly higher payment.