Clearly you will test a small hidden area before applying any different paint.
Ive found that Two pack paints are perhaps "rather unlikely" to apply reasonably over old deluxe.
Other way around, - praps - but ive found my International two pack cures like liquid steel,
Impervious to fuel spills, albatross poo and strangely even "paint remover"
I tried it on test and the two pack sat there enjoying the expectant look on my face.
Nowt 'appened.
If "dulux" worked so well, why not repeat - opens up your palette to shades of pink sunset etc