I believe picobrew recommends a max of 1.5oz per cage...I assume to allow for expansion once the pellets get wet. You can do as Denny suggest by using a pause step in the advanced editor. If I am looking for a big 10min addition I often just program one for 11min and one for 10min and split the addition between 2 cages if I am not using all 4.
Keep in mind that it takes 5 min. for all the wort to circulate through. So a 10 min. addition would be like a 2 min. addition on another system.
Took me some time for me to figure this out and adjust for it. Been brewing on the Zymatic for a couple years now and am finally getting my hoppy beers where I want them. The pale/ipa systems from my 'traditional' system relied on larger doses of very late hops, I've had to both up the hops like Denny mentioned, spread out when the hops are added and move them up in time to get my hoppy beers to turn out like I expected.
I mostly do 3.5 gallon batches with OG's of 1.045-1.052 which is possible on the Zymatic, you just start with a full keg of water. For my beers that depend on a l lot of late hop character I will often do 1.5 oz additions at 21 min, 14 min, and 7 min. For comparison that about seems to match what I'd get out of my 10 gallons system with 8 oz of hops added (to a 10 gallon batch) at flameout and and whirlpooled for 15 min before chilling with a plate chiller. That results in more of a hoppy but not too bitter beer, to get more bitterness I'd suggest just adding some to the beginning of the boil to reach your bitterness preference. The IBU's calculated for the late additions on the Zymatic are useless, interested to see what data Denny gets back.
Pretty sure the adjustments needed to hop timing are why some Zymatic users aren't happy with their hoppy beers. I had to figure it out with a lot of trial and error.