Regarding removing channels from measurement result headers and coloring the headers in channel colors.
In single-channel measurements, this looks fine, as in the top item on the screenshot. But what about measurements involving two channels, as in the bottom item on the screenshot? Color the parameters as in the middle item? Won't this make it difficult to quickly read the results?

You could remove it as well, once it's understood that tapping expands/collapses the items the arrow becomes useless.
In the expanded item, you still need to designate the area that you click to collapse

Besides, the size of the expanded item is already quite large, an extra 5 pixels will not play a big role.