Your estimates sound about right to me. Coast to coast is always the most expensive in the CONUS. USPS has a 108" total girth limit before bumping to oversize. FedEx and UPS is 130" I think. Not sure how you were shipped a 64cm frame via USPS for $25. Does the seller work for the post office? USPS is the cheapest if you can keep the box smaller than 108", but that only happens with very small frames, as you mention.