Sorry - wasn't flaming you - I thank you for taking the time to post this here. I just want to keep facts on the table.

I'll assume for a minute the analytical numbers are correct. Let chat about the two of over 20-25 numbers you typically get on an analysis sheet.

TBN=Total Base Number - this is chemically (on an acid-base scale) an amount of base added to a new motor oil to nuetralize any acids. Acids that come from blow by, condensation in the oil, contamination, etc. Notice the words in his post "your engine is depleting this". This tells me something about his engine - there may be something wrong and the oil is doing it's job. The oil is not crapping out. His conclusion is incorrect. For what it's worth Amsoil 5W-30 starts at 11 TBN, not 12. (Most petroleum oils start at about TBN 6 or so)

Viscosity is at 100°C. His oil started new at 11.7 cSt. An increase of 0.9 cSt to 12.6 is not alarming. The oil is a 5W-30 and yes the upper limit on NEW straight SAE 30W is 12.5 cSt.

By his own admission (and ommision): "Everything else looked good..." this means wear metals (critical!!), oxidation (a real measure of how the oil is holding up!) What was the lab's conclusion?

The statement that the Amsoil "not holding up" makes me call BS, that's all.
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http://www.fidalgo.net/~brook4/oilslubesfilters.html