Here's my version:

\function .firstnchars(n) [split[]first<n>join[]]
\function phone.area-code() [.firstnchars[3]]

\function .is-toll-free() [phone.area-code[]] :intersection[enlist{TollFreeAreaCodes}]
\function .is-local() [phone.area-code[]match{CurrentAreaCode}]

\function phone.toll-free(number) [<number>] :filter[.is-toll-free[]]
\function phone.local(number) [<number>] :filter[.is-local[]]
\function phone.long-distance(number) [!phone.local<number>!phone.toll-free<number>then<number>]

\procedure call-type()
  <% if [phone.local{!!phone}] %>
    local
  <% elseif [phone.toll-free{!!phone}] %>
    toll-free
  <% elseif [phone.long-distance{!!phone}] %>
    long-distance
  <% else %>
    INVALID PHONE NUMBER TYPE
  <% endif %>
\end

This is a drop-in replacement – the <<call-type>> procedure call will continue to operate as before.

A few things to notice:

• We added .firstnchars and phone.area-code functions to avoid unnecessary duplication and make the logic easier to read.
• We have an <% else %> clause which, if we wrote the wikitext correctly, will never be used. Because most of us unfortunately do not write perfect logic every time, this is a useful way of validating our assumptions (here, that if a phone number is not local or toll-free, it is long-distance). Should this assumption ever prove untrue, perhaps because there's a mistake in our definition of “long-distance,” we'll see a message INVALID PHONE NUMBER TYPE on the template instead of a blank space, making both the fact that something is wrong and exactly where the issue is coming from abundantly clear. In general, obvious errors should be preferred to silence – if the error is hidden, it's much harder to find the mistake, and you might not notice it at all until you make faulty decisions based on wrong information!