I reckon you're looking at a body in the system map and seeing that the breakdown of the materials to be found on it, in this case it told you 5.5% Germanium. Then what you're doing is landing on the planet and driving around, following the signals on your SRV scanner, this is why it is leading you to things like canisters guarded by skimmers.
Here's what you do.
FSS the system, it will tell you the same information, this body has X amount of carbon, sulphur, rocking horse poo, and then it will tell you, in the upper right hand corner how many POI's are on that planet. So then you fly over to that planet, and use a DSS, fire some probes at it and it will tell you, once you hit 100% where the geological sites are. They show up in your nav panel or as locations on the planet surface. Now you can fly directly to the site where you will find numerous chances to collect numerous materials.
Lets say that you land at one of these sites and you still only pick up a few Germanium samples, well you would also have picked up a load of different ones too, maybe carbon, sulphur or rocking horse poo.You can take those materials to the Material trader (you have to find the correct one, search the forums) and you can trade the materials you don't use for the ones you want.
This has been explained several times in his other thread, I think we are wasting out time!