If it is in writing he will honor it. The parent company is does not want their reputation damaged.
Don't kid yourself. I have several buddies in the consulting/services biz that have been screwed by big clients. One guy finally had to hold a key piece of work for ransom so he would get paid and that was with a fortune 100 company. SOWs and contracts allow you to take a client to court and you might win but you NEVER want to go there.
"Billy, we're looking at the same numbers it's pretty cut and dry- I think we can both agree that there is massive potential here... This is exactly why people like you hire me. I specialize in getting business' quality clicks while your competition languishes being status quo. Do you want status quo or would you prefer a proactive approach to your webpage clicks?
All we need to do now is simply set up an appointment, which time is best for you? And will all decision makers be present? If yes "great" if no- "Okay, to be sure everyone's questions get answered we require all decisions makers to be present at our meetings, which days work for them? Please remind them it'll only take 10-20 minutes"
Then Pre Qualify before the apt so you have all the answers that they need to make a decision on YOU. Prequalify 100% of the time.
Ask him how he'll know he has the right company, they'll tell you exactly what you need to give them to make a decision. Bring the your stats vs the competitions stats (if they're complimentary, which they sound they are).
How soon would they like to make a decision? If there isn't a goal set, set one for them. And then use your stats to show how much money they could lose if the wait a long time, also show them stats of how much extra they'll make with your product.
You're a small company, you want to please them even more than the other company, you have a proven plan to get them to higher #s, it's already working. You have the time and resources to tailor your program specifically for their needs.
I would sell it as OK you're a head of a new division, you can stay as you are just being average or you can hire us now and be a hero. The raw numbers are there, what kind of additional revenue with that 2.5x increase bring?
In my business, when it all boils down they client only cares about 2 things:
How much is it worth, how long will it take to sell?
I translate this to your situation to "How much revenue will we see from your service, how long will it take to see profits from clicks"
Then do 1-3-5 year forecast of page clicks. Figure out the ratio of how many page clicks it takes to sell a product, or money made per click for the company.