How is it that lo loestrin fe can work with only 2 placebo pills compared to the normal 7 days of placebo pills?

Placebo not needed: the spacing only helps to prevent bleeding at unexpected times

Not important: The placebo pills do not play any role in efficacy of ocp's. As long as you take the active ones, you can take any number or no placebo pills and the pills are equally effective. The role of the extra two estrogen pills is to shorten the amount of bleeding you have on the current pill you are on.