Hey!

I'm not sure I've understood you right. Actually, experience points allow you to level up your Haven but they are not giving you additional offensive or defensive bonuses. 

And why do you think your defensive/offensive bonuses do not work? Please, give me more details of your issue, Captain. 

When you're offense and or defense boosts are active it shows up here:

the experience boost though not sure where that shows up. I haven't used any yet. Don't really see the point to leveling up anymore.  Really don't see the benefit unless someone else knows a benefit other than bragging you're X level. As an fyi level isn't a deterrent. I've seen lv 40s that are stronger than lv70 players