Hi soundphase,
My findings confirm yours. Registrations do not retain the internal parameter changes (generally) to Insert DSP's used in styles, and apparently that includes changes to levels. Only the default levels are returned, normally 127 (although Delays have lower default levels, 32 or so). If you want to keep the changed values you can either save the style with the changes, (the set level will be returned) or save a user DSP while the level is changed then resave your registration.
Another option is to add the DSP as a System effect and set the Send appropriately. Those Sends are saved in Registrations.
John