Comparison of the theatrical version and the longer American TV version, featured on the Anchor Bay DVD. Altogether 4 chapters of the TV version were shot after the original shooting had ended. That happened, by the way, during the shooting of Halloween II.
Theatrical version: 1:30:13
American TV version: 1:41:00
Difference: 10.47 Min. altogether

0:07:00
Dr. Loomis argues with 2 other doctors about transfering Michael Myers to a minimum-security-sanatorium. Then he briefly visits Michael and tells him that he might fool them. But not him...
339 Sec

0:20:08
Dr. Loomis takes a look at the room where Michael was held in the sanatorium and managed to escape.
103 Sec

0:34:43
Laurie gets a visit from her female friend, then girl talk...
205 Sec