It depends. has to be compared with the PHC eco strategies with refineries i think. Less stock but more constant income versus lower income but better stock for substrate. (and better peaks with orbital boost?)
Also with the PHC orbital boost for the productivity of factories and consequently the income/expense flux ratios.
Still have to test things and don't exactly remind what were the PHC refineries precise specs in base Ashes (price, construction time, region eco boost was 20% if i remember well), but i found myself constructing them more rapidly in escalation.