Leaders block artillery LOS but often cannot be hit or only on a 1 in 36 chance

I believe it is the case that a lone leader blocks artillery LOS? If so, and without card bonuses, when the leader is 2 hexes away he can only be hit 16/216 (~7%), when 3 hexes away he can only be hit 1 in 36. If he is 4 hexes away he can't be hit at all absent cards. Is this how others interpret the rule? It could be viewed as temporary fieldworks, smoke or entrenchment I suppose, which is destroyed or cleared when the leader is forced to retreat under fire.

Substantively correct, but there is a 100% chance the leader must evade 1-3 hexes when attacked, even by ranged combat. So a very temporary block. 
www.commandsandcolors.net/napoleonics/th...ics-expansion-5.html

Probably worth mentioning the lone leader is also an impediment to movement. Lone leader is something of a misnomer in my view, it is the General and his staff.