Relocation Reimbursement

Our company is relocating its headquarters in CA to another city that is farther than the current location and it has triggered an actionable event situation. They gave everyone a notification letter which stated what relocation benefits would be available. The letter I was given stated the following under the heading "Relocation Benefits": "Your relocation benefit is a lump sum amount of $xx,xxx gross ($xx,xxx net) if you own your present home and $yy,yyy gross ( $yy,yyy net) if you currently rent. Additionally, COMPANY NAME will provide informational support to assist you with your move. To be eligible, within one year of the office move, you must move to a new residence within 15 miles of the new office unless the company approves a variance based on access to public transit. This benefit is intended as an incentive for you to stay with COMPANY NAME." The following question was posed to Sr. Mgmt regarding this benefit: "As a homeowner, I would like to evaluate the possibility of keeping my home and renting a small apartment for use during the week. Will the relocation benefits apply in this scenario? " The Sr. Mgmt response: "Yes, if you own a home and then move into a rental closer to the office, you will be eligible for the renter benefits rather than the homeowner benefits." My question pertains to the legality of stating one thing in our offer letters "lump sum amount of $xx,xxx gross ($xx,xxx net) if you own your present home" then reducing the relocation benefit to the renter amount because we cannot sell and buy a new home. Is this legal for the company to reduce the lump sum for homeowners after having stated it in our notification letter? The letter makes no reference to purchasing a new home only moving to a new residence within one year. Additionally, there was no accompanying material laying out the specific costs to be reimbursed just the lump sum based on if you are a current home owner and move to a new residence within 15 miles of the new office. Is this legal for the company to pull bait & switch? If this is not legal, what can I do about it?