It will be mostly arrival (since controling gets you access to the facilities usually) but not always.
I'd be interested if theres any corrolation with between this chart and start times (given I have an afternoon start, unlike last time getting up to Malton with a bunch of time in hand is more dependant on sleep needs)
Those with an afternoon start have and afternoon finish (if they need it - full value).
You have literally no need to "get up to Malton with a bunch of time in hand".
Getting back to Malton (1132km), though, as Phil has shown; it increases a rider's chances of finishing in time to have 7+ hours in hand. Please recall that all the riders in 2017 who wanted to know, were fully aware by Brampton on the way back, that there would be a stonking headwind across the fens.
So arrive in 83 hours from starting. Start 1400 Sun : get back to Malton by 0100 Thu and sleep, leaving by 0600, say. The rider has 15 hours of daylight, 7 hours of dark (some sleeping, YSPMV) and another 9 hours on Friday. 386km in 24 hours of daylight riding time. 7 hours stopped overnight, 5 hours at controls (very generous) and the 'on the road' speed needed is 20kph.
Anyone who doesn't think they can maintain 20kph rolling for those last two days will need to ride some dark hours and spend less time feasting at the controls. One of the benefits of night riding (eg for the flat 120km south from Horncastle) is that the (head)winds are often lighter at night.
The food at controls will be excellent. In time-straightened circumstances, faffing (eg updating your insta story) is not excellent. This is of course an entirely personal choice. But I'd like to welcome riders back to Loughton in time, not hors delai.