So, I referenced my spreadsheet of past event costs. Here are the past prices for Adv Refine Runes. And sacks always cost 10 coupons, adv runes always cost 6 points. And until 5.0 the points per food sack was just shy of 2 points/sack (1.9).

12-21-2017--- 30 coupons per rune

1-18-2018--- 30 coupons per rune

2-15-2018 --- 30 coupons per rune

3-15-2018 --- 30 coupons per rune

4-19-2018 --- 30 coupons per rune

5-10-2018 --- 30 coupons per rune

6-14-2018 --- 30 coupons per rune

7-12-2018 --- 30 coupons per rune

8-9-2018 --- 30 coupons per rune

9-6-2018 --- 20 coupons per rune (drop rate changes to 3 points/sack)

10-4-2018 --- 40 coupons per rune (sack price raised to 20/sack)