I referred to a friend in ExxonMobil and this is what I can share regarding a 8-5 job maintenance technician salary structure. For shift hours.. Im not sure.

AWS-Fixed 3 months.
Variable Bonus - Range from 2 months or ++, Maybe like 2.2,2.3...
Long term allowance - $100 per month?

As for gross salary. Diploma Experienced.. Min 1900-2100...
With annual increments based on performance ranging from $100-$300..
Technicians can progress further with a long time career..
Lets say u start from trainee with a gross of $1700.. As you progress to Senior,, Your salary can reach $3000-$4000+!!

I belief Shift technicians will be able to earn more due to shift allowances, OT, etc..