  We explored in Chan et al. 2024 how the ion-electron temperature ratio
affects certain numerical models of Sagittarius A* (Sgr A*). Specifically, we
studied these effects in magnetic-dominated regions in magnetic-arrested disk
(MAD), focusing on the $3$-hour variability at $230$ GHz -- $M_{\Delta T}$. In
this study, we investigate how variations in electron temperature prescription
parameter, $R_{\rm Low}$, influence $M_{\Delta T}$ by analyzing a series of
general-relativistic raytracing (GRRT) snapshots. In certain black hole models
with a spin $a > 0$, we discover that increasing $R_{\rm Low}$ renders the
photon ring more optically thick, obscuring the varying accretion flows that
contribute to the variability. However, as $R_{\rm Low}$ increases further, MAD
flux eruptions become more pronounced, compensating for the decrease in
$M_{\Delta T}$. For models with a spin $a < 0$, although a higher $R_{\rm Low}$
also increases the optical thickness of the fluid, voids within the optically
thick gas fail to cover the entire photon ring. Similarly, flux eruptions are
more prominent as $R_{\rm Low}$ increases further, contributing to the observed
rise in $M_{\Delta T}$ against $R_{\rm Low}$. For black holes with $a \approx
0$, although the effect of increasing optical depth is still present, their
$230$ GHz light curves and hence $M_{\Delta T}$ are insensitive to the changes
in $R_{\rm Low}$. Furthermore, we find that the variability of the $230$ GHz
light curves at $R_{\rm Low} = 1$ correlates with fluctuations in the internal
energy of the gas near the black hole, indicating that unusual gas heating may
be the source of significant $M_{\Delta T}$ seen in simulations. Our findings
highlight potential approaches for refining $M_{\Delta T}$ to better align with
observations when modelling Sgr A* or other low-luminosity active galactic
nuclei.
