Safegraph Spend: New Release compared to Past Release

Hello,

I recently downloaded the most recent Safegraph Spend data and was comparing it to Safegraph Spend data that had been downloaded from maybe a year or so ago. I was surprised to see that there were differences in the most recent and old data in months that they matched. The data seemed to match for most of the rows, but there were some POI that only had spend in the new release and some that only had spend in the old release.

I assume that it is better to use the newest release, but I am just curious as to why Safegraph would change their data for past months. I was under the impression that the Safegraph Spend data would not change, but it appears that they have deleted and added rows at some point. Any insight into this would be appreciated.