Only the 182 Shiki increases in damage.
In the lab right now. Orochinagi does 190 uncharged. Charge for one second, it does 210. Two seconds does 240. Max charge does 270.
Respectively, 182 shiki does 165 uncharged, 179 for one second, 222 at two, 241 Max.
EX Orochinagi, with the same charge times, does 313, 342, 370, and 399.
EX Shiki, 328, 356, 385, 423.
This can be useful; st. C xx df. X xx qcf D D > orochinagi does 272 is the orochinagi is done immediately. If charged a little, it can do 288.