Many piccolo sets are designed to have similar tension to a standard 105-45 set when tuned octave-up EADG, perhaps because manufacturers assume the player won't want to (or does not know how to) adjust their trussrod. However thinner strings have a higher 'perceived' tension or 'feel' and actually do not need as much tension to keep vibration 'tight' and under control because they have less mass. A lower tension is optimum, healthier and more playable, so just detune until it feels right to you (and adjust the trussrod if necessary).