Have one more point to clarify.
According to SGHA point 1.2, we should be charge either invoice item 4 OR item 5.1, 5.2 whichever is lower.
As item 4 is lower, we should only be charged item 4 and not item 5.1 and 5.2.
Item 5.1 and 5.2 on request and recharge basis should not be applicable for this case because aircraft return to ramp.