This is what Frank Lobitz writes in Kampfpanzer Leopard : Entwicklung und Einsatz in der Bubdeswehr(Development and Service in the German Army):
Talking about the 8th production batch:
"In contrast to vehicles of the sixth and seventh production lots, those of the eighth production lot features light side skirts that incorporate D-technology. (KMW)"
Further, he goes on about the prototypes for the 2A5:
"....A maximum of 62.5 tonnes was set as the weight limit. Chief efforts were conducted in the field of armour protection. The add-on armour packages were designed with D-technology(similar to fourth-generation spaced composite armour) and,depending on their location on the vehicle, were either integrated(turret front/chassis) or mounted on the top(turret roof). For the first time add.on armour modules were mounted in front of the original armour of the turret front and chassis, and this changed the appearence of the vehicle significantly."
Sorry for barging in to your conversation and if not understanding your question..