I couldn't tell you what I have set for that. I think I set my delay for 10 minutes to save the compressor. Even .5C is plenty small enough of a differential. The yeast won't be affected by that much of a change in 10 minutes. Even if your chamber temp was considerably off and your 10 minutes allowed the ambient temp to change a LOT, your wort isn't going to react that quickly. It's got thermal mass.
Consider when you place your hand on a frying pan you JUST set on the stove. When you turn the heat on, you don't instantly feel the heat (If you have a pan with a thick bottom (Thermal mass.)) It takes a few seconds for the heat to transfer through the pan bottom.
Same with wort. It tends to hold temps a bit because of the mass. The outside edge may change temp quicker than the inside temp, but the inside wort is helping to temper the temp change at the outside as well.
So in summary, It's All Good, Baby!