I have no one intention to changing your mind.
From the bottom of my laziness I went to check and I've just edited my previuos wrong post proving why millis () is not a good way to count accurately time if you don't take into account the error it introduces: millis() increments the counter every 1.024ms !!!
You have to handle this for an accurate clock using millis() function, this is the point!
There is no example to write, but only datasheet and source code to read, examine (and possibly understand).
Off course, an RTC is far away the better choice for this kind of problems, but this is not what OP has asked for (and in any case it has already been suggested to him).