Sheets report pulling inaccurate data

[SThom...@ahslink.com]

For the reports I'm running on total transactions, transactions by device category, and transactions by medium, in the past 2 days the total transactions has been lower than the sum of both transactions by device category and transactions by medium. Additionally, neither number matches what I find in GA. None of my reports are sampled (in GA Premium, or the sheets add-on) and all the results found were returned.

How can I trust the data in these reports when none of it aligns?