What does +1 do on upgraded support skills?

Hi!!!

What does upgrading polish, swindle...etc do?

Anyone has a list about these upgradable support skills?

[Koenaj]

It depends on the skill.
Skills that raise stats will simply raise it *2.

Swindle becomes multi-target once it's +1, meaning both your opponents will lose 1PP.
Lethal Powder will give the stacked Poison Buff immediately upon usage.

Those are the only two skills I can think of right now, if you find any others, let me know !

I searched some of my monsters and found that
Feign Weakness and Leaf Sheild could be upgraded,
dont wanna try yet coz its too pricey to test.

500k silver and 200 essence of wisdom for +1 LOL

[Koenaj]

I searched some of my monsters and found that
Feign Weakness and Leaf Sheild could be upgraded,
dont wanna try yet coz its too pricey to test.

500k silver and 200 essence of wisdom for +1 LOL

Feign Weakness decreases it's ATK with *2.0 its original decrease.
Leaf Shield increases your DEF with *2.0 its original increase.

It might be worth to play around with these skill upgrades, especially Sword Dance and Polish.
Altough it won't be of any help in Ladder, when facing Pegasus' in PvP that can remove PoD, Sword Dance+1 or Polish+1 can be a good alternative!