The "unit offer:" and "unit mass:" lines show the value and mass of the quantity the player has. The text below states how many they are willing to purchase, but the screen doesn't show the total value or mass of the quantity they are willing to purchase. The latter seems more important and less misleading, although displaying both sets of information might be useful.

george moromisato 9 Nov 2017:

Fixed in 1.8 Alpha 4. Thanks!