50 month Guarantee my buttocks! Read the fine print!

I needed my truck the other day to move garbage, so I went to the garage to start my 1985 Ford Ranger. My battery was dead. Been over a month since I last started it. So I plugged in my handy dandy jumper box and jump started my rig. I then drove it around the peninsula to charge my battery. I parked it near our house and a few hours later I tried to move it. The battery was dead once more. So I figured the battery was not charging, hence, it was dead. But lo and behold, I had the guarantee in my glove box intact! I read the guarantee and it said the battery was good for 50 months and I checked the purchase date and seen I had bought the battery at Les Schwab 48 months ago! Sweet! I would get a new battery! I left the battery for a check in the morning and came back a little over an hour later. They confirmed it had bit the dust. Then I was informed that if I look at the warranty provisions, I would only get a replacement if the battery failed within 12 months. After that, the prorated percentage of time used would be discounted for a new purchase. So, since my battery lasted 48 months out of the 50 months they guaranteed, I would only get a 4% discount on a new battery. Damn. Should have read the fine print. So those 50 and 60 month printed guarantees on a battery should be well read!