seems every form has a different position in different sects. in core Shaolin temple materials, they consider it the first pugilistic form, whose 18 techniques, before being evolved into a pugilistic art, have been a Qigong set, derived from the older sets, like Shaolin Ba Duan Jin. so they call it 'xian tian Luohan/Damo 18 Shou,' where the name implies it has been the first martial set. Luohan/Damo is a religious aspect, the set has been created much after Damo. there's a manual of the set when it has been a Qigong set, before being evolved to a pugilistic set (notice the Ba Duan Jin and Yi Jin Jing like postures, and also compare it with Deyang's form and look how Shaolin martial arts have emerged out of ancient Qigong sets):
先天罗汉拳十八手图势
this manual has been published in 1926, when headmonk Miaoxing broke the ancient traditions and let the documents go out of the temple and be accessible to the public. just i can't read the Chinese text, it must have valuable notes. anyway, many manuals of Shaolin temple kung fu had copies in other temples and families. i don't know where this one comes from.