Yes, this is why I never recommend 100 gpd systems to anyone. I try to tell everyone who is interested in buying an RO to make sure they don't buy the 100 gpd to try to get the word out since many people have no idea.
For those that already have 100 gpd RO systems, it is easy to change. You just need to buy whichever membrane you want, and a flow restrictor that matches the gpd rating of the membrane. Bulk Reef Supply has them readily available for very reasonable prices.
www.bulkreefsupply.com