And again, it's critically important to separate the different "trade ecosystems". Bulk cargo and passenger transport between large, developed systems is going to use highly optimized infrastructure that keeps the ships in motion as much as possible. Small-scale speculative or spot-market trade of the sort PCs typically conduct is much more likely to follow the week-in-jump, week-in-port rhythm because you need the week in port to sell your current cargo and find new cargo and passengers.
Trade "pipelines" also effect the economics, and hence the optimal ships used. A perishable or fad item has much higher value if it gets to its destination as quickly as possible. A bulk raw material doesn't, as long as there are steady deliveries at the destination world that roughly match the rate of consumption. Nobody cares if it took a week or a year for each load of unobtainium ore to arrive at the industrial world that needs it.