On near white surfaces there is an increasing difference in indirect light intensity for each surface bounce, between Enlighten and Progressive Lightmapper.

(See images below)

1. Open the attached project LightIntensityPVRvsEnlighten'
2. Open the scene 'spotlight enlighten pvr compare'
3. Let progressive finish auto bake
4. Switch to Game View or select Main Camera and Menu>GameObject>Align View to selected
5. Switch Lightmapper to Enlighten
6. Observe the difference in diffuse bounce light

Other things to try: (no particular order)

Select both Plane - floor & Plane - roof and apply the different white value materials (200, 225, 245, 255) and obersve the increasing mismatch
Hide the Plane - roof and see a near match between the lightmappers
Set indirect multiplier on the spotlight to 0

Tested with 2017.3.0b5