Confusion from extend-type/extend-protocol example

[cobalamin]

https://github.com/swannodette/lt-cljs-tutorial/blob/master/lt-cljs-tutorial.cljs#L1335-L1355

These lines of code and comments seem to suggest that there is some sort of real difference between extend-type and extend-protocol:

;; Or you can extend a protocol on a defrecord.

I wasn't sure, so I read up on them in the docs. The docs for extend-protocol state:

Useful when you want to provide several implementations of the same protocol all at once. [...] Expands into calls to extend-type

So am I right in assuming that extend-protocol is but a convenience macro that always expands to extend-type calls? If so, the marked lines seem a little bit odd, as we're getting nothing out of using extend-protocol instead of extend-type for a single defrecord, the syntax just seems flipped around and it left me thinking there was a fundamental difference between the two.