I am a bit confused. I see people being granted for residence visas with salary less than $55000 through the accredited employer. Their previous visa was open work visa. How is this possible?
No idea. You can see the rules, as can anyone. If someone tells you, 'Oh, but X did this, and he only had (whatever),' the chances are that you are not hearing the full story, or a correct story. I'm afraid we often see evidence of an aspect of human nature on the forum, that people seem to WANT to bring those applying for a visa all kinds of gossip that will unsettle them and make them doubt that what they are doing is correct, or possible. It makes sense ONLY to go by what you can see on the INZ website
https://www.immigration.govt.nz/new-zealand-visas, or in the INZ operational manual
http://onlineservices.immigration.go...nual/index.htm. After all, you can imagine that approaching INZ with a reason such as 'I ought to have a visa, because Fred at work said his brother got one' is NOT going to be any use.
If your employer is accredited, you don't have to have an essential skills visa before applying for a Talent (Accredited Employer) work visa. If you're on a visa that will cover you for the next year or so, so you would be legal while processing was going on, then yes, you could apply directly for residence under SMC. The reason most people get a work visa and THEN move on to applying under SMC afterwards is that a work visa can be processed in 1 - 2 months, so they can start work without keeping the employer waiting too long for their new employee, whereas an application under SMC can well take around a year.