AS far as I'm concerned... the float test is MOSTLY checking the size of the air cell that has developed. Though rotten ones should be putting off more gasses and floating higher like yours did. Otherwise, they should all have a little floating direction where the air cell is IMO.
Refrigerate them eggs!
Listen, while it is OK to leave eggs at room temp... the fact of the matter is
they age an equivalent of 1 week per day on the counter compared to in the fridge. It SERIOUSLY impact the quality of egg within... the yolk and the white become runny. The whole point of having our own eggs aside from knowing how the birds were treated is to have fresh eggs that far surpass supermarket. In my fridge I have eaten eggs that were 6 months old and STILL on par with store eggs.
I have had some that were stored out on the counter for long periods of time... without turning... OK, back peddling here just a bit... left out long enough there is a lot of evaporation that actually makes the internal eggs thicker and sometimes the yolk will stick to the shell.
I think storing eggs on the counter is a novelty for chicken owners. If they aren't being eaten that day or very soon, I NOW choose to refrigerate. I NEVER EVER wash them, the bloom helps keep them fresher, longer.
The eggs I left out for long periods... the only ones that got rotten were ones that had their shell compromised in some way. A crack or toe nail poke... but I'm sure there could be porousness that effects it.