MTUS and ATUS confusion

I am confused by how much information from ATUS is inlcuded in the MTUS? When I run frequences for country of birth using all samples of the MTUS- I find a limited number of countries
However, analyzing the ATUS generates a huge list of country of birth

For example, no one born from Phillipines in the MTUS data across all the surveys

The availability tab for BTHPL shows that this variable is currently only available for four samples: Canada 2015, Israel 1991, Italy 2008, and United Kingdom 2014. Moreover, only the UK 2014 sample allows for responses from a sizable number of countries.This is why you’re not seeing as many countries being represented in the MTUS. While included in the questionnaire, the BTHPL variable was not consistently offered in the version of the ATUS data that IPUMS MTUS uses (as well as a number of other time use surveys included in MTUS). However, the IPUMS Time Use team is planning to include this variable for ATUS samples in a future MTUS release, and hoping to make BTHPL available for other samples (new and previously released) if we can secure the corresponding/relevant/more detailed version of the original data.