Arms Lore Bonus is pretty much tied to Arms Lore only. So, it won't go over the 8 Resists/8% DI applied on top of the base for exceptional crafting on Siege (5 Resists/5% DI on the other shards), but still requires the item to be exceptional to be applied.
Exceptional Chance improves for items at a 2/1 ratio from 0-95 skill, increases to 5/1 for 95.1 to 100.0, then goes back to 2/1 after 100. (Normal crafting is a flat 2/1 for most skills, though some items start at 50% chance, and others at 0%)
Using an item that is 80% Normal chance to make, 20% Exceptional at 90 skill, as an example.
94 skill: 88% Normal, 28% exceptional.
95 skill: 90% Normal, 30% exceptional.
96 skill: 92% Normal, 35% exceptional.
97 skill: 94% Normal, 40% exceptional.
98 skill: 96% Normal, 45% exceptional.
99 skill: 98% Normal, 50% exceptional.
100 skill: 100% Normal, 55% exceptional.
101 skill: 100% Normal, 57% exceptional.
110 skill: 100% Normal, 75% exceptional.*
120 skill: 100% Normal, 95% exceptional.
* (Note: This is the point where, if a 120 PS is used, you would stop getting a gain on this level of item crafting difficulty on the other shards (as the gain limits are based on the Normal item creation chance (before being rounded down to 100%) being less than the Power Scroll value). Talisman bonuses don't apply to the skill gain chances. I have no personal experience, though, as to how RoT gains are affected by that system).
BUT.....
Smith's BODs improve dramatically at 110 and 120 real skill (ASH bonuses do not affect BODs).
70-109.9 = 50% Iron Weapons, 25% Iron Armor, 25% Colored Armor BODs
110.0-119.9 = 50% Iron Weapons, 15% Iron Armor, 35% Colored Armor BODs.
120 = 50% Iron Weapons, 5% Iron Armor, 45% Colored Armor BODs.
So, if you are going to do BODs to get your own Runics and other rewards (talismans that prevent ingot loss on failures, talismans that give 100% smelt chance for specific metals, maps to mine specific ores and get that ore every dig), you will want 120 Smith, and the higher skill will also make it easier to fill some of those BODs.
Tailor, it's only bonuses to craft (normal and exceptional) over 100, but if you ever find yourself making Studded Armor, Bone, Hide, and other high-difficulty armors (which the changes to non-med armors now giving a form of passive LMC have made attractive again), you'll want both 120 skill and a good Tailor Exceptional Bonus talisman. 120 scrolls were ludicrously easy to get before the BOD revamp, and are even more so now. Arguably, having 120 Tailor is probably more valuable on SP than on the other shards, since you are far more likely to be crafting replacement armor. But whether it's worth it to you is a matter of your personal experience.
