Under what conditions can you use Table 4E4 for cable calculations?

If you have multiple installation conditions, it may be that the terminations are running at 70°C but the cable reaches 90°C elsewhere, which might relieve a constraining condition. For example, if the cables are buried in the ground, but there is sufficient exposed length in air to cool before the terminals.

(Of course in other factors such as sheath temperature also need to be considered)

It rather depends on the additional correction factors for grouping, routing and burial and so forth - the switch gear may be well ventilated and the cores of the wire well separated so at 70C or lower, while  the cable rating is set by part of the cable further along that is grouped, or buried, or in some other way not optimally cooled. Or indeed in reverse you may step up a cable size for the last metre of cable in the switch room if the cooling there is especially awful due to grouping etc.
On a 200m run however, I'd want to check that volt drop may restrict  the cable size rather than heating. (or leave no allowance for VD in the later wiring.)
Mike.

edit sorry composed this at the same time so cross-posted/

Actually there is a simple way to overcome this problem, and that is to splice a short length of the bigger cable onto you 90C rated smaller size, you need enough length say 1m so that the thermal conductivity does not transfer some of the heat, and that the joint is adequately ventilated. However in this case I suspect that you are volt drop limited anyway, and the larger cable size will save its cost difference in saved electricity quite quickly. Typically such joins may be crimped or bolted crimp terminations on each cable.