Christ is Born!
I believe the Jordanville Unabbreviated Horologian tells exactly when they are done. The HTM Horologion is very good, but it is too bad it does not tell when they are done.
The Unabbreviated Jordanville Horologion wrote:According to present-day udage, the Inter-Hours are said only on the first day of the Apostles' Fast and on the first day of the Nativity Fast if it begin on a weekday. When the Inter-Hours are said, there is no Liturgy. According to the Nikolsky Ustav the Inter-Hours are not appointed during Great Lent when the Kathosmata and readings from The Ladder are appointed at the Hours.