As the author of PriceAdvisor, I'll try to answer this:
This is a consequence of PriceAdvisor's not-so-clear handling of "expected results". Checking the wiki, we see that using a floaty inverse geode gives:
7-10 sand
2-6 pebbles
0-2 gravel
0-1 rocks
What PA is trying to say is "turn whatever stuff you get into rocks (buying whatever extras you need to do so), and make rock lobsters", but it's not very good at communicating this because
a) it doesn't know how to talk about expected results very well, although it does the math correctly (i.e. it calculates profit as if you get .5 of a floaty rock, but it outputs stuff about 1 floaty rock)
b) it doesn't account for things like using the sand you get from the geode to make pebbles, which you can use to make gravel, which you can use to make a rock, so it treats each result separately.
So what it is trying to say (and utterly failing to communicate) is:
use 1 floaty inverse geode;
This, at least, is easy to understand!
acquire 4 floaty gravel; make 1 floaty rock; acquire 1 wok lobster; make 1 rock lobster; mallsell 1 rock lobster;
Get however many gravel you need to make a rock with the gravel you have. Make the rock, get a wok lobster, make a rock lobster, and sell it.
acquire 4 floaty pebbles; make 1 floaty gravel; acquire 4 floaty gravel; make 1 floaty rock;acquire 1 wok lobster; make 1 rock lobster; mallsell 1 rock lobster;
Get however many pebbles you need to make gravel with the pebbles you have. Make the gravel, and get however many gravel you need to make a rock. Make the rock, get a wok lobster, make a rock lobster, and sell it.
acquire 1 wok lobster; make 1 rock lobster; mallsell 1 rock lobster
If you got a rock from the geode, get a wok lobster. Make a rock lobster and sell it.
acquire 4 floaty sand; make 1 floaty pebbles; acquire 4 floaty pebbles; make 1 floaty gravel; acquire 4 floaty gravel; make 1 floaty rock; acquire 1 wok lobster; make 1 rock lobster; mallsell 1 rock lobster
Get however many sand you need to make pebbles with the sand you got from the geode. Make the pebbles, and get however many more you need to make gravel. Make the gravel, and get however many more you need to make a rock. Make the rock, get a wok lobster, make the rock lobster, and sell it.
I realize this is almost completely opaque, and I apologize. Better output for expected results is something I am working on, but Real Life has been pretty heavy with the time commitments lately.