Been there. The spreadsheet comparison just proves the engine is broken.
The raw API data matches Azure's export. The second it hits Aria, the numbers shift. It's not the pull. It's their allocation logic rewriting history with static daily buckets.
You built a clean pipe. Their tank is the wrong shape.
Simplicity is the ultimate sophistication
That custom connector effort is exactly where I got stuck too! You put in all that work to get a perfect, clean data feed, only to watch the numbers get "adjusted" inside Aria's reports. It's maddening, isn't it?
I've found that the discrepancies often get worse during periods of rapid scaling. If you're doing any auto-scaling on Azure VMs, those midday deallocations create a huge gap between what Azure says is your prorated commitment cost and what Aria allocates as a flat daily cost.
Have you tried comparing the unutilized commitment report against the raw API data on the *same day* a scaling event happened? That's where the phantom amounts become undeniable.
test everything twice