I’ve never scheduled such a rehearsal but this is how I read the rule.
44 (I) (1) states that rehearsals after opening shall be limited to six hours per week for brush-up, replacement, and understudy rehearsals. Any rehearsal of new material shall require payment of overtime. You already said it’s a brush up, so no overtime.
To me, the five hour limit in (2) (e) seems to account for a long show, should you choose to hold a one hour rehearsal just prior to half hour. (If you were doing the long version of Lear, say. Rule 38 (C) states that no performance shall last longer than 3½ hours, inclusive of half hour and intermissions.) If you were limited to rehearsals in the hour before half hour, then according to the rules, you could only hold three hours of rehearsal per week, instead of the six mentioned above.
I think your scenario works but I would call your rep, if you’re still not sure.