Notwithstanding xberk's advise, which is immediately appealing in your case, you need to get a handle on just what Pan/Crop is and what it is meant to do. Simply put, P/C does exactly what a Camera does: You Pan Left, your Subject appears to move Right. You Tilt UP and your Subject - this Logo - appears to move downwards. Tilt upwards far enough and it will "slip" further out of Frame until it will have totally disappeared. There is a perfectly good reason why there is that "F" greyed-out indicator on the P/C Screen, "F"rame.
OK, now back to the option of using Track Motion.
Pros:
• We get the image located where we want it. In a sense, Job Done!
Cons:
• We now have a complete Track being controlled/used for this Logo. This can be messy and a drain on processing.
• Unlike Pan/Crop, using TM results in a reduction in resolution. Again this may generally not be an issue, but may impinge on the retention of resolution much preferred in a Logo.
My Preference would be to produce a Graphics solution for this, meaning, in a Graphics package place the Logo in a Plate that reflects your Project Template. If 1920x1080, then start with that and locate the logo in the preferred position. Save the Graphic in PNG format to retain transparency, and import the Logo.png straight into Vegas. You'll need to activate the Alpha channel to get the transparency active. You'd now have a discrete Event on the Timeline without using a TM control using up processing and the best clarity.
Your call, try both methods, but I wanted you to explore another option that you could very well benefit from. Also there will be others reading this too!
When you're in the Pan/Crop window, right click and select Match Output Aspect. Now zoom out and reposition as necessary and your logo won't disappear.
Yes, there have been many times i've wondered why 'Match Output Aspect' isn't the default when using Pan/Crop. It's always easy enough to change back, but in the majority of cases this seems more useful than matching the input.
I struggled with understanding Pan/Crop for 2 years before it finally came to feel natural - move the cursor to the right, image moves to the left. What made it clear to me was analyzing its name - "Pan". You pan a camera, you move or slide an image. So the tool is clearly the camera and it makes sense.