Yup, that's one of the reasons you do the follow-up meditations. ;-)

The reason is that your subjective impression of the quality of a scrying need not have much to do with how well you connected to the theme of the scrying; a lot of extraneous factors can get in the way. To use some old-fashioned occult jargon, your subjective mind (aka subconscious) can absorb much more than your objective mind (aka consciousness) can process, and meditation is one of the ways you can tap into the latent perceptions of the subjective mind.