I don't have much trust in a battery that is more than about 4 years old. The life span of a battery is on average 4 years give or take. I'd rather replace it at 4 years old than get stuck at a bad time on the road.
On a fully charged battery, 100 amps for 10 seconds @ 10.40 volts is weak. Without even trying it, I can tell you it won't pass 50% of its CCA for 15 seconds.
The CCA has to be somewhere around 280, maybe even 300. A number that the Moco supplied, not one we made up. So 150 for 15 seconds @ 9.8 would be just passing. Plus think of the extra labor that is being placed on your stator & regulator...
I would change it.
Well, I've been around here long enough to know that when Glider and Hoople advise you on something, and they both agree, then you better listen! Friday's pay day - I guess I'll be off to the dealer for a new battery! And yes, I'll charge it all the way up myself before installing it.