The percentage liability staking plan is identical to the fixed liability staking plan except that the liability is linked to a percentage of your bank.
For instance if, your start bank is £100 and the percentage liability setting is 5% then your liability will be £5.
If the bank increases, so will your liability. If the bank decreases, your liability will also decrease.

In TSM there are several further options including a ratchet mode.

Windows Desktop TSM Version 7.0

Evaluation version of TSM is restricted to 10 bets at any one time. No time restrictions in place. 

Web Based Version - TSMapp

Login as Demo User. Restriction of 10 bets at any one time.