you may post your concern in http://forum.hentaiheroes.com/index.php?/forum/14-suggestion/ . i doubt it's considered a problem. it's xp amount that's supposed to match since it is the main reward whereas an item's a mere bonus. Doesn't feel like a waste to me: contributes to daily 150 kobans.
Considering the need for affection points atm one should just buy all the gifts out of every stock regardless the price per point, why bother? as for books i'd choose the change on how excess points after maxing the lvl stack over $/xp.