size consistency in solvents

Dear CCL members,
 This question is regarding calculation of activation barrier in
 solvents for a bimolecular reaction and about a possible existance
 of size-consistency. Is it acceptable to calculate the energy
 differences of the transition state-in-solvent with respect to
 the sum of the energies of individual reactants-in-solvents?
 These bimolecular reactions are radical-molecule type reactions
 in gas-phase and the overall charge of the reaction is zero.
 Calculations are single-point SCRF PCM/MP2/6-31+G** for all reactants
 and the hydrogen-abstraction transition states
 Any reference, comment and/or suggestions are highly appreciated.
 Thank you,
 Sreedhara
 Dr. Sreedhara V Rao  Dept. of Chem., WSU, Pullman, WA-99163.
    voleti()at()wsunix.wsu.edu   or voleti()at()wsu.edu