Compressive Modulus of standard clear resin

We performed compression test on clear resin cylindrical specimen according to ASTM D695 (Standard Test Method for Compressive Properties of Rigid Plastics).
Post curing was done using CureBox (https://wickedengineering.com/curebox/) in ideal conditions as mentioned in Dr. Zguris’s paper (https://formlabs.com/media/upload/How-Mechanical-Properties-of-SLA-3D-Prints-Are-Affected-by-UV-Curing.pdf)

However we obtained a compression modulus of around 147 and 167 ksi, which do not match with Dr. Zguris’s tensile modulus of ~410 ksi. We were expecting that the compressive modulus should be at least equal or higher than the tensile modulus.

Has anyone performed the compressive strength test on clear resin ?

Does anyone have any insight on why we are not getting a modulus of ~410ksi ? Does anyone have any suggestion (ex. post curing) so that we could get a modulus of ~410ksi ?