I know what diesel regen is (was a class A truck/coach and automotive mechanic for about 25 years) so maybe I can help. You've shown the desired result but what's missing is what your data looks like. Also, I see nothing in the result that indicates which engine/vehicle this is for, so that's important too. If you really want to shorten this, post a db with some sample data. Alternatively, you could copy/paste & post (you should get a table here). A spreadsheet(s) as an attachment would be good, but a db would be best.
Worst case scenario, you might need a subquery.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.