About the front pointed canisters, I think it is likely that they contain a red phosphorous based smoke agent, while the upwards pointing launchers contain a brass flake obscurant. Both work in infrared, but brass flake has worse properties for blocking in the horizontal. 
RP like in ROSY here has better properties horizontally as it has a curtain like effect but wont properly obscure the vehicle from above as the burning elements will fall on the vehicle and the ground, neither of which is desirable.
So the front smokes are RP for horizontal blocking while the vertical launch smokes are brass flake for better top coverage properties.
RP like in ROSY here has better properties horizontally as it has a curtain like effect but wont properly obscure the vehicle from above as the burning elements will fall on the vehicle and the ground, neither of which is desirable.