If-Range and cache validation using Last-Modified

Part 5 section 5.3 If-Range has the following text in the case that the response has no etag and only Last-Modified.
 If a client wishes to perform a sub-range retrieval on a value for
 which it has only a Last-Modified time and no opaque validator, it
 MAY do this only if the Last-Modified time is strong in the sense
 described in Section 2.1.2 of [Part4].
Section 2.1.2 in Part 4 has this text:
 o The validator is about to be used by a client in an If-Modified-
 Since or If-Unmodified-Since header field, because the client has
 a cache entry for the associated representation, and
 o That cache entry includes a Date value, which gives the time when
 the origin server sent the original response, and
 o The presented Last-Modified time is at least 60 seconds before the
 Date value.
This seems to exclude If-Range which is strange since the If-Range text pointed to this section. Is it possible to add If-Range to the text in the first bullet point, or make the text more generic such that it doesn't exclude other methods that use the Last-Modified time?
Thanks,
Matthew