Unrealistic Total-Bytes-Written on SSD

Question

At a customer's site, I have a small server with a (small) SSD. The server is in operation for about 5 years, and the SSD status looks like that, according to the manufacturer's tool:

This looks too good to be true! And, apparently, it is too good to be true, since the numbers don't check out:

• Today's screenshot shows that 0.58 TB have been written so far.¹
• However, we perform rotating local backups of the ~10 GB worth of SQL Server databases on the server every night (keeping the last 3 days and deleting older backups).²

Thus, ~10 GB of new data gets written to the SSD every night, which makes ~300 GB = ~0.3 TB of data every month. This strongly contradicts the fact that only 0.58 TB have been written over the last 5 years.

Is the ADATA tool broken or do I have some fundamental misunderstanding of the "Total Bytes Written" metric?

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Footnotes:

¹ The raw SMART data (if relevant) can be found here and here.

² Yes, I know that local backups are not a viable backup strategy. Of course, we also have off-site backups!