I've got thousands of hours in this game and I still haven't bothered to try to figure out how science works with respect to transmissions, experiment resets, the processing lab, etc etc. It's all so very arbitrary and unintuitive.
There are some simple changes that would help a lot.
For example, temperature readings, gravity readings... basically any "pure data" part should be able to record and transmit as often as you like. And it should so so for full value. Transmitting a temperature reading home provides exactly the same information as writing it down and handing it over when you land.
Samples, on the other hand, should be single use and should only provide two options: either process them in the lab, or bring them back to KSC for a larger "processed in big lab back at KSC" reward.
Also, that should be the only function of the mobile lab. "Cleaning experiments"... I don't even know what this does, but I don't think it makes any sense. You don't clean samples, you clean your apparatus... which is the lab itself in this case, so what the hell does this even mean?
You'll notice that there's absolutely no mention of transmission loss. That's because transmission loss doesn't make any sense. Once I have the data it makes no difference whether I carry it home or send it home. The difference with being at KSC is that the labs are better and can get more data out of a sample. Hence the larger reward for returning samples.
Now, whenever I write this post (and I've written it several times) someone always mentions that "in real life" you can get different data by observing/experimenting on materials in space, and so the mobile lab should provide a different reward, not a fraction of the "return home" reward. But this is exactly the function of the materials bay - a single use item that provides information about a particular sample at a particular biome - so there's no need for the mobile lab to do the same thing.
TL;DR: - Non-sample instruments can be used an infinite number of times. - Samples can only be used once and must be processed somewhere. - NO TRANSMISSION LOSS.