When you use the BIP39 option in Electrum, I believe that it doesn't check spelling or the checksum of the seed etc... so you have to be VERY careful when typing the seed in.

Also, if you have put in a seed you believe to be 100% and it shows nothing... double check the derivation path that you used... Electrum defaults to m/44'/0'/0', but for MultiBitHD it should be: m/0'

NOTE: The apostrophe after the 0 is VERY important... so again... it is: m/0'


As for the different balance when importing the private keys... MultiBitHD and MultiBit Classic are two different wallets. MultiBit HD did not allow the import of MultiBit Classic keys... you had to send the coins from MBC to MBHD.

So the keys from MBC will not be the same as the keys for MBHD... so the balances in the two wallets will be different.