Ahhh... A Sigma and 150-200mm, 1/3s shots! No wonder you're getting along better. Are you working unguided?
My D5300 + scope were at 621mm and my PA exposures had to go out to about 15s with that combination (trudge, trudge).
So I had both the slow exposure rate and the folder setup/teardown time - just didn't make sense vs the faster guidescope w/ its camera.
Mounts: ES PMC-8 EXOS2
Scopes: SV 102EDT, ZWO 60/280 Guide
Cameras: Nikon D5300, Altair GPCAM2-IMX224C
Software: ASCOM, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer: Thinkpad x230, Win7Pro/64