gst on commission paid

if sale of 3390+18%gst including gst is made
and commision on base amount of sale is 30%+18%gst....and commission agent is from another state..
what should be the tally entries when commission is paid/deducted by commision and remaining amount is given back to us.......

from my point of view

when sale is made...

1. xzy @ 18%......dr rs 3390
cgst9%.........dr. rs 305
sgst9%.........dr. rs 305
To sales xyz............ rs. 4000

2. when commission is paid a jv is passed....

sales xyz......dr. rs1200
To commission...... rs.1017
To igst........ rs 183

from this i can get the ITC on gst and also gets net amount actual sales made...
please suggest me is this method of accounting is right ya wrong....