Thanks Chris, a number of my eggs have tipped slightly to their ends when they were about to hatch and had the same 'springiness' about them. I can't remember whether they are eggs that succeeded in hatching. I know some that were springy in the R-com incubator lost their springiness and ended up dead in shell.
I am checking the R-com 20 again. It is not the R-com Suro that you had, but made by the same people. The humidity looks fine, but at floor level in some areas it is about a degree too cold. This perhaps explains why the hatches have been low and why some have hatched late.