you can set a custom fee as per this guide:
https://bitcoinelectrum.com/how-to-manually-set-transaction-fees/I Do you not want to pay 7% in fees? If not then you can move the slider that should appear to within 5 blocks (an hour) or 25 blocks (5 hours).
Fee are not calculated in percentage (%) but in size and weight (Satoshi/vbyte).
when the fee is unusually high as a percentage of the amount you wish to send electrum warns you about it so you don't end up spending more on fees than you want to. this warning is what the OP is talking about.