It is possible that his telekinetic powers contributed to the strengthening of his psionic whips, which are in actuality just a visible mental projection that allow Marc to manipulate matter with his mind. For instance, if one did not see the whips, it would appear that Marc was picking up an object, or slicing an object in half with telekinetic abilities, so it can be argued that Marc's stronger psi-whips are due to his telekinetic powers becoming part and parcel of his psychic energy whips.