First of all Saturn posited in Leo is not good as it is sign of Inimical Sun. Saturn in 10th house brings delays and obstacles. Saturn is the planet of hard work, but in inimical sign even hard work doe not pay. Retrograde effect would be more when Saturn becomes Saturn becomes Retrograde during transit. Saturn being a malefic planet would give malefic results more strongly. Debilitated Saturn in Navamsha is not good , you should do the remedies of Saturn for benefits.