Openrocket and RASAero II Predicted Altitude Difference

[utkan.kya]

I am working on a high altitude rocket powered by Aerotech L1256WS-PS and targeting above 10000ft. I first designed this rocket on Openrocket, where I saw a peak altitude of 11453ft and a maximum speed of 315m/s. Then I did the same design on RASAero II, where I saw a peak altitude of 9224ft and a maximum speed of 274m/s. When I removed the outriggers from the simulation, I saw a peak altitude of 11719ft and a maximum speed of 317m/s on Openrocket. When I did this on RASAero, I saw a peak altitude of 10855ft and a maximum speed of 281m/s. At this stage, I don't know which one I should trust. What do you think I should do? Altitude sensitivity is very important for me. Some technical specifications of the rocket are given below.
3.38 inch Body Diameter
57.87 inches Rocket Length

 

[drewnickel]

Some things to note:

Flight Modeling:
OR is quasi-6DOF (the quasi meaning the aerodynamic coefficients are assumed to be axisymmetric and so your yawing coefficients are the same as your pitching coefficients, etc, but the simulation itself has up/down, left/right, forward/back, roll, pitch and yaw).
RASAero is 3DOF (Up/down altitude, up/down range, and the pitch axis).

Drag assumptions:
OR uses assumptions based on the Barrowman methods, which are fine for subsonic flights but aren't great in the transonic or supersonic regime.
RASAero is essentially Missile DATCOM, a semi-empirical tool that has been validated by wind tunnel and flight testing and is the industry standard for first order aerodynamics modeling

Other things:
OR allows eng, RSE or RASP files as well as extensions to simulation options
RASAero assumes you have a "traditional" rocket design, and also does base drag corrections for power-on/power-off

Each of them have their benefits and drawbacks. For simple designs I don't care much about accuracy on I stick to OpenRocket. When I get into the nitty gritty details I use the Cd Override plug-in to import aerodynamics from RASAero and the multi-level winds plug-in to get an idea of where it will land on launch day. In general, the aerodynamics model in RASAero is better than in OR, but OR supports additional functionality.