We say:

If a call on accumulator-before or accumulator-after is evaluated for a streamable accumulator then:

The evaluation must occur in the course of evaluating a pre-descent or post-descent instruction in some streamed template rule T, respectively

This appears to rule out accessing an accumulator as the last thing done within an xsl:stream instruction.

We should generalize the rules about pre-descent and post-descent instructions to cover the sequence constructor in xsl:stream as well as that in a streamable template rule.