Umm... The Arabic 'year' is just plain weird. I don't know how they use it for anything except religious calculations.
The Arabic Calendar(Hijra Era) is a plain lunar calendar. A lunar calendar is based on the revolution of the Moon and is not connected to the solar year of 365.25 days. A lunar year is 354 days long, with alternating months of 29 and 30 days. It starts on the day after the new moon and ends on the next new moon. The lunar year is 11 days shorter than the solar year. So 33 lunar years make 32 solar years.
In Hijra Calendar, no effort is made to correct the years to the solar years. But in luni-solar calendars extra months are added to tally the lunar months to the solar years. 96 solar months are equal to 99 lunar months in length. Hence if 3 lunar months are added in 8 years period, both systems can tally. This method is employed in Hindu Lunar Calendar. Buddhist Calendar is also a lunar calendar as the full moon days are important in Buddhism. It is believed that Lord Buddha was born, got enlightenment and died on full moon days.