I am trying to work with the 'Find Similar Locations' analysis tool in ArcGIS Online, and I have a question about 'Base similarity on' section:

The options that appear are only a small fraction of the fields within my database, and after a bit of comparing I have found that the fields all have a data type of 'Double'. Is there a reason for this? Is there a work-around or a way to have all fields show? The returned options severely limit the comparison, and make the tool pretty much useless for me.
If all of the fields within my database were present this would be an awesome tool!
As always, thank you for any suggestions or insight in advance! (I'm pretty sure that this time it's not user error, I could be wrong though...)
Dell OptiPlex 9010
Intel(R) Core(TM) i7-3770 CPU @ 3.40 GHz
8.0 GB RAM
Windows 7 Professional 64-bit OS
AMD Radeon HD 7570
Dual Dell U2414H Monitors