In some cases, the Purchase Value may not match the numbers shown in the Meta Ads interface. This often happens when purchases come from omnichannel sources (e.g. offline sales or mobile app conversions), which are not included in the standard purchase_value
field.
Try using the omni_purchase_value
field instead.
This field includes all tracked purchases, whether they happened online, offline, or through mobile apps, giving you a more complete view.