"Question. Does a lower CRM for Q4 2018 of (US$7.77/bbl) mean that they are making less profit than Q3 2018 at (US$12.17/bbl)?"
Yes, all other things being equal, they are making less profit than in Q3, 2018.
But only in their Refinery business.
Which, at the current level of refining margins, will not even come to even one-fifth of CTX's total operating EBITDA
The remaining, non-refining Caltex businesses, i.e., Fuels and Infrastructure and Convenience Retail - which represent that largest part of Caltex's earnings base and valuation - would be making more profit today than pcp.
For context, here is the EBITDA breakdown of business segment, as at the FY2018 interim result:
