So from the start of the event I tracked my stats to try and compile some more info on the event. Here are my findings:
Day 1 : 9 scroll drops for 42 instance sweeps (drop rate 21%)
Day 2 : 14 scroll drops for 42 instance sweeps (drop rate 33%)
Day 3: 9 scroll drops for 31 instance sweeps (drop rate 29%)
Day 4: 7 scroll drops for 39 instance sweeps (drop rate 18%)
Day 5: 48 scroll drops for 179 instance sweeps (drop rate 27%)
Day 6: 14 scroll drops for 41 instance sweeps (drop rate 34%)
Day 7: 18 scroll drops for 40 instance sweeps (drop rate 45%)
Total drop rate of 29% or an average drop rate of 30%
Total points earned during event was 965.
So looks like the drop rate for scrolls in this event is somewhere around 30% which means statistically a player will get 15 scrolls a day meaning a total of around 105 scrolls which will be a min of 525 points. This of course is just natural energy not counting stam pots.