All things considered, I can't see how you could have made a better choice. BC's are excellent and this may even be a better constructed bullet than the NOSLER partition, which is one of the best. Pricewise, the Interbonds are less expensive than the Swift A-Frame. Plenty of bullet for a premium hunt!
As far as weight, the rule of thumb for Elk is a minimum Sectional Density of .260, which the 180 meets and the 165 may not. The 165 would make for an excellent trophy Whitetail or Muledeer load. Over time, I believe the Interbond will prove to be one of the best controlled expansion/high penetration bullets on the market with few peers in Ballistic Coeffecients!