In the wiki (https://safenetwork.wiki/en/FAQ#What_is_safecoin.3F) there is:
If there is a safecoin there, the attempt fails. If no safecoin currently exists at that valid safecoin address, the network creates a safecoin and enters the public safecoin address of the successful requestor, whether it be the Farmer, App Builder or Core Dev pool. The recipient of the safecoin then holds, transfers or spends it as they choose.
From above it seems that safecoins are indivisible, i.e. you can’t have 0.5 savecoins for example. Is that the case?