BC: ExCAA mentions that taking insurance at below designated TC is an even money bet.

"Insure when the count is exactly zero, insurance is an even bet , so you may wish to
good hands for cover or variance-reduction purposes (insure soft hands, and 8- 11, 18-21)."

I'm fairly sure that only applies to SD. However, does that also apply to 6D/8D?

TIA.