Based on the Admin API documentation, tabs and lines are different types of metrics incorrectly.
The problem:totalTabsShown and totalTabsAccepted are specifically for tab completions (autocomplete suggestions), while totalLinesAdded/Deleted and acceptedLinesAdded/Deleted are for code edits (from chat/composer features).
Correct approach:
For tab completions only:
Total suggested = totalTabsShown
Total accepted = totalTabsAccepted
Acceptance % = totalTabsAccepted / totalTabsShown
For code edits only:
Total suggested = totalLinesAdded + totalLinesDeleted
Total accepted = acceptedLinesAdded + acceptedLinesDeleted
When calculating overall (sum) numbers for my devs, too, the acceptedLinesAdded seems to be more than totalLinesAdded, which make my acceptance % > 100%.