Strange cam specs

If you're on top of the lifter plunger, there's no way you can know if it's collapsing some or not. It's an inaccurate measurement. As long as you think it's good, carry on.
I posted here because I know you guys have a lot more knowledge on this stuff than I do. I'm not arguing, I'm trying to understand.

The only weight on the plunger is the weight of a carbide pilot (that is being used in place of a pushrod) and the spring pressure from a dial indicator. I'm sure the total pressure on the plunger is less than 1 pound. That cannot collapse a lifter. So why is the measurement inaccurate?