Yes, it MUST use. If everything else is "must", what do you think exempt foreign property is exempt from the "must"?
And in prior years, foreign property *IS* included in that list, but the law was not changed in that regard in 2018, so it is likely just an oversight in whoever wrote the revised Publication.
<a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-prior/p946--2017.pdf#page=30">https://www.irs.gov/pub/irs-prior/p946--20...>
Again, I don't see ANY leeway here. The law is quite clear based on the context.
