I am the shipping manager at FrogStore.com. My store name is Bullfrog, but my real name is Randy.
All Frog Store employees have more that one duty, so I am not the only one to do shipping, but I do it more than anyone else.
Another of my duties is to monitor published shipping rates from the US Postal Service and FedEx and occasionally update our in-house shipping practices. USPS rates are cheaper for light weight shipments, and FedEx Ground is cheaper for heavier shipments. Where the transition happens is what I watch for. FedEx also charges more for residential and rural addresses, which complicates our decision making.
I will make a separate posting about how you can predict how long it will take for your order to reach you.