  The COSMOS field has been extensively observed by most major telescopes,
including Chandra, HST, and Subaru. HST imaging boasts very high spatial
resolution and is used extensively in morphological studies of distant
galaxies. Subaru provides lower spatial resolution imaging than HST but a
substantially wider field of view with greater sensitivity. Both telescopes
provide near-infrared imaging of COSMOS. Successful morphological fitting of
Subaru data would allow us to measure morphologies of over $10^4$ known active
galactic nucleus (AGN) hosts, accessible through Subaru wide-field surveys,
currently not covered by HST. For 4016 AGN between $0.03<z<6.5$, we study the
morphology of their galaxy hosts using GALFIT, fitting components representing
the AGN and host galaxy simultaneously using the i-band imaging from both HST
and Subaru. Comparing the fits for the differing telescope spatial resolutions
and image signal-to-noise ratios, we identify parameter regimes for which there
is strong disagreement between distributions of fitted parameters for HST and
Subaru. In particular, the S\'ersic index values strongly disagree between the
two sets of data, including sources at lower redshifts. In contrast, the
measured magnitude and radius parameters show reasonable agreement.
Additionally, large variations in the S\'ersic index have little effect on the
$\chi^2_\nu$ of each fit whereas variations in other parameters have a more
significant effect. These results indicate that the S\'ersic index
distributions of high-redshift galaxies that host AGN imaged at ground-based
spatial resolution are not reliable indicators of galaxy type, and should be
interpreted with caution.
