Non-functional movement – 18 years

Well, I am still in confusion. I am bit confused on the statement in the GO# 181-SE. The GO states:
“shall be placed in the next higher grade pay of the same pay band or
lowest grade of the next higher pay band”
What does it mean by “or lowest grade of the next higher pay band“? What is the application of this rule? Why did not the GO say only “next higher grade pay of the same pay band“?
Could anybody clarify the above?
Regards,
Tapas

The Teacher (staff) belongs to up to Pay Band-3 will get 18 yrs benefit.
Now there are 4 scale in pay band 3 with respective grade pay- 3200, 3600, 3900 and 4100.
If a teacher belongs to scale no. 11 i.e in pay band-3 with grade pay 4100 then after 18 yrs of continuous satisfactory service he/she will achieve scale no. 12 in pay band-4 with grade pay 4400 with same designation.
Why did not the GO say only “next higher grade pay of the same pay band”?
If the G.O says this then the staff belongs to pay band-3 with grade pay up to 3900, will get the facility. To get the facility for the scale no 11 also G.O says ‘or lowest grade of the next higher pay band’.