Going back to the OP question, the 4.8 is a good figure, however you may or may not have had a liver dump as you could have been higher than 4.8 pre-breakfast? We just don't know unless you did do a pre-breakfast test?
But what ever you are doing keep doing it - seems to be working for you.
It is perfectly normal for the liver to do a glucose dump when the body needs it, as already mentioned, what some people forget is that the body will then need to top up the glucose store afterwards - normally just after an insulin user has injected a correction dose!