Indeed. Just to anchor this with current state-of-the-art numbers, I took a look at the CSV data file linked to by the page referenced in my above comment:

https://news.ycombinator.com/item?id=13040765

The quoted horizontal standard errors of the daily position measurements are ~1.5mm. The vertical standard errors are ~5-7mm. (Not as bad as a factor of 10, but certainly worse than 2x.)

The vertical position measurement responds well to averaging of daily errors to beat down the RF propagation effects that cause them.