It says the time I brew my time depends on the strength of it. Does this also mean the caffeine content is?!

Not really. About 80% of the caffeine is extracted in the first 30 seconds, so most will be extracted during the normal brewing time. Of course, if you use loose tea (which can be used several times, there won't be much caffeine in the subsequent cups, even though they taste almost the same. So if you want to reduce the caffeine, let it steep for 30 seconds, dump the liquid & brew a second batch.

The longer you brew your tea, the more caffeine will be leached into your cup. What's on the box is the average, and if your using bags or measured spoonfuls, then the variance isn't going to be significant. However, id you do what my sister used to--using two bags in a regular 8oz cup--your caffiene content is going to be significantly higher. And if you re-use teabags, then the second cup will have very little caffeine.

Not sure lol