KoA's answer seems good to me, but I see another interpretation of the wording: 4 is a time of day and 22 is a number of hours. This time, "adding 22 to 4" means adding 22 hours to 4pm, getting 2pm, or adding 22 hours to 4am, getting 2am.
This is consistent with the 24-hour clock but doesn't require it.
4 is a time of day and 22 is a number of hours. This time, "adding 22 to 4" means adding 22 hours to 4pm, getting 2pm, or adding 22 hours to 4am, getting 2am. This is consistent with the 24-hour clock but doesn't require it.