If you just add up all the "percentages" it comes out to 97, and there are 100 box units in the drop. So, those ratios are nearly 1:1.
In other words, they have 1 Modern Masters 2015, 1 Modern Masters 2017, and like 7 boxes of Theros. It's a weird drop.
AtriumXPA quick add shows you only have about a 15% of getting a box worth greater than or equal to the drop price and an 85% chance of overpaying for a box