Combined road/trail movement

[J6A]

So, here's the way it affects things.

2 MP units
3 road (3 total)
2 road, can't move a 3rd onto a trail (2 total)
1 road, 1 trail (2 total)
0 road, 3 trail (3 total)

It seems odd that the combination could cost them a hex of movement.

3 MP units
4 road (4 total)
3 road, 1 trail (4 total)
2 road, 1 trail (3 total)
1 road, 2 trail (3 total)
0 road, 4 trail (4 total)

Again, there are 2 spots where it loses 1 hex.

5 MP units
7 road (7 total)
6 road, 1 trail (7 total)
5 road, 1 trail (6 total)
4 road, 2 trail (6 total)
3 road, 3 trail (6 total)
2 road, 3 trail (5 total)
1 road, 4 trail (5 total)
0 road, 6 trail (6 total)

Same deal.  2 spots where it loses a hex.

So, what I'm going to say is that if a unit moves exclusively on roads and trails, it can move at least 1 hex more than its base movement allowance.