Some info on ROS (in General)

Me vs The Twin Towers

Tower of Strength cast Dispel Magic on all enemy Minions (111,899)
Aprentice cast Ablative Shield on all friendly Minions (32603)

Me vs shield

wimpygirl cast Dispel Magic on all enemy Minions (123,784
Aprentice cast Ablative Shield on all friendly Minions (29938)

Me vs Extreme Newbie
Kemuri cast Dispel Magic on all enemy Minions (150,548)
Aprentice cast Ablative Shield on all friendly Minions (19019)

A Rune of Solitude lvl 195,420
Ablative Shield: 79,888 (38,356) from home page

SO suspect it around .7 for 1 level

forget to mention that vs twin towers my base prot make it alive

1) DM reduced by 106,146 - 94.86%

2) DM reduced by 115,366 - 93.20%

3) DM reduced by 131211 - 87.15%

Not sure how the base protection survived in 1)... But this seems to indicate reduction is not a straight figure like the ToE.

did you include the reduction from 3 minion

I'm hoping your AS casts at (38,356) normally. Is this not the case?

Aprentice cast Ablative Shield on all friendly Minions (32933)

I did take my FF off for having the same amount of minion/familiar.I have train about 30K exp so that why it a bit higher that report higher in the treads.