Matching Stains

I’m building a hall tree for my house and I’d really like to figure out how to get the stain to match the mill work. I took a piece off that is getting replaced anyway to my local Sherwin Williams and they compared it to the Minwax display and said here you go. Me not really convinced by this bought one of those little sample sizes just to be sure and stained a sample. It looks like it’s the right color but way too light. I’m going to put another coat on tonight and see if it improves but if not is there someplace I can take my sample in and get stain matched up at?

-- Trust me I'm an engineer.