Based on these premises, we have developed a composite method, referred to as the "cheap" scheme (ChS) and devoid of any empirical parameter, which has provided accurate structural and energetic data at non prohibitive costs. In conjunction with geometries and harmonic frequencies computed by double-hybrid functionals, ChS has given promising results also for the activation energies of some reactions of astrochemical interest. In analogy with the W1X 17 and SVECV-f12 18 composite methods, ChS employs second order Møller-Plesset perturbation theory (MP2) for estimating CV correlation. Further reduction of the computational cost is achieved by performing, in analogy with the corre-lation consistent composite approach (ccCA), also the CBS extrapolation at the MP2 level. Quite recently, an improved variant (referred to as the jun-Cheap scheme, junChS) has been introduced, which, thanks to the use of the "june" partially augmented basis sets of the "calendar" family, provides accurate results also for non-covalent interactions and activation energies. In the present paper we perform a comprehensive benchmark of the latest member of the "cheap" family of composite methods, junChS-F12, for several classes of reactions for which accurate reference results are available or have been purposely computed. We will show that, thanks to the replacement of conventional post-Hartree-Fock methods by their explicitly correlated (F12) counterparts, this model chemistry improves the accuracy of previous variants, strongly reducing the uncertainty of CBS extrapolation without any excessive increase of computational requirements. Together with electronic energies, we analyze also reaction rates employing the master equation approach based on the ab-initio transition-state theory (ME/AITST).