The Phased Retirement is fine if you plan on actually retiring but if you want to get another job, the ramp down screws up your ability to work full-time for someone else. You also risk getting a ramp down longer than you wanted (you don't get to choose, HP chooses) or they extend it beyond what was originally agreed (and they can do it.)
I had two friends that wanted 6 months, were given 12 months and then got extended to 18 months. If they didn't accept it they lost all of the benefits of early retirement and were just terminated.
If you are planning on not working for up to 18 months it could be ok although my attention span would go to zero quickly.
Bumped from @YtChRh0-hrju for important info.