Hello, Archon!

Well, let's clarify some points regarding Persian Positions:

1. I would not suggest sending Imperial Units to PPs. To get profit from the PPs, send the weak units to the battles to exchange them for stronger troops. 

2. Persian Positions are more about exchanging Units. But still, apart from Units, you receive Experience and PP Tournament points, etc. at the PPs. Those things are very important and help to advance in the game. Please do not forget about it when you estimate your PP rewards. Another and one of the most important aspects of rewards is General Gear. PPs gives items that enhance Units' strength or can be destroyed to upgrade other Items. Attacking PPs of higher levels gives more chances to receive rarer, better General Items.

3. So many men, so many minds. I'll give a chance to other great warriors to share their tips and suggestions on this subject.

From what i  saw mate  like all others features  in this   game if u want greater rewards  you also have  greater losses.So off course  you will lose a more troups  in higher levels to get an payout . The payouts   are the same proportionally  on high and low  levels    ..things wich  are different it's the better general items  ... and  the amount of the resources  you have to invest  to get the same thing as the low levels guys in raport of losess

So my advice it's not to go  for oracle to level 180 because it's isn't worth it , the game works fine  :) 

A doubt about the positions. When it gives you the good payment in a Nv.98. For you to get another good payment you have to be in a higher level position or you can give it in a lower level.