The App shows free postage when it’s not

[maryandmiff]

I’m relisting my items with Simple Delivery, for which I’ve selected buyer to pay but the App is advertising it as free even though when you click through it shows the buyer to pay, I think, unless I’m misunderstanding this?
(I don’t want complaints from buyers and I cannot afford to offer free postage now when it is not within my control, many of my items are very low value.)
Advice gratefully received. 

[maryandmiff]

On another item, which does say buyer to pay, it shows as £4.65 but then when you click into it it says £4.27 ?

I’m going to stop relisting, there must be a problem with the settings and display on Simple Delivery.