To get other calculations on a complete rebuild, call at least two other insurance companies.
Also, you can't use the purchase price for your calculation because it includes the value of the land - so if using - and you back it out - you may be at the dollar amount you see fit.
Yes, I have had this happen and trust me - your agent, like mine, will sell you any policy you want to buy. Get a good explanation of the policy in its entirety. Although it may seem your coverage is depleted, "layers" will kick in due to other provisions.