Nice try. I had it tested about a year ago they said it was fine... I'm leary of the results.
Ya, current testers only give a general assessment of the battery's true condition.
Getting a fast and dependable assessment of a failing battery is difficult. Most battery testers in use only take cold cranking amps (CCA) and voltage readings. Capacity, the most important measurement of a battery, is unavailable. While taking the CCA reading alone is relatively simple, measuring the capacity is very complex and instruments offering this feature are expensive. BEST BATTERY = most expensive
IMO, Interstate is a better built battery than most, but you pay for it.
Crappy Tire sell the worst and the cost reflects that. I believe they are or up till recently are Exides. Wally World are from Johnson Control, but probably still made in China.
If you want to get good life out of a battery, remove from vehicle and shake it like a can of paint. That will reverse acid stratification. Essentially when this is done the acid rich electrolyte lying on the bottom will remix with the acid poor electrolyte in the top half. It's the acid poor top half that kills the plates.
Recharge discharged batteries after a good shake at no more than 4 amps/hour. Avoid if possible 40 or 60 amp/hour charging units.