  The inflationary paradigm not only addresses early Universe puzzles but also
aligns well with the observational constraints, with slow-roll inflationary
models fitting best. Evaluating these model predictions requires considering
both slow-roll inflationary dynamics and the subsequent reheating epoch. This
involves the quantitative analysis that takes into account the effective
equation of state (EoS) and duration of reheating, connecting these with the
perturbations generated deep during the inflationary era. Given the
complexities involved, many approximations are often used for simplification.
However, as future observations are expected to improve the accuracy of these
observables significantly, this work takes a different approach. Instead of
relying on approximations, we consider the near-accurate solutions of
inflationary models and compare our results with the pre-existing ones. It
mainly incorporates two improvements: the first is the accurate dynamics of the
slow-roll evolution, and, thus, the end of inflation; and the second is the
higher-order slow-roll corrections to the perturbed observables. Our findings
indicate that, by implementing these corrections, the theoretical predictions
improve significantly. It also indicates that seemingly minor corrections can
have significant effects on the perturbed observables, and these refined
predictions can be compared with future observations to potentially rule out
models and help resolve the degeneracy problem of the inflationary paradigm.
