VideoStudio :: X3 - Why Is The Same As First Clip Option Grayed Out

I shoot AVCHD video from my Canon Vixia HF S 21 at the highest setting of 24 Mbps / 60i. I have a Lite-On BD Burner and make BD-R discs. Originally when creating the movie that will be burned to disc, I was using the Blue Ray option (MPEG2 25000kbps). I was not happy as I saw much degradation of the image. I know from users on this forum that H.264 is the prefered format, but VS X3 limits you to 20000kbps, which will result in an even more degraded image. (Will this limit be removed in VS x5??)

What I found by accident was in the above project, use the option "Same as first clip". This resulted in an H.264 video, VBR 22700 kbps and the video is very sharp on my 55" LCD TV compared to the MPEG2 compression. So I am quite happy with this setting.

My problem is on my project right now, the Same as first clip option is grayed out. Why is this happening? Could it be that this time I captured as real 24F rather than in 60i format? My only option is MPEG2 for BLuRay, or use MPEG optimizer which still shows Mpeg2 but now VBR is 22700 rather than 25000 kbps. There is no way to get it to render as H.264. BTW I also noticed this the other day when rendering a project from video from my wife's Flip camera.