The phrase "adding to the extent" is correct and usable in written English.
It can be used when discussing the degree or level to which something is being increased or supplemented.
Example: "The new policy is adding to the extent of our current benefits package, making it more comprehensive for employees."
Alternatives: "increasing the degree" or "enhancing the level".
"We're putting this vote forward so we can turn the heat up back home," Mr. Santorum said, adding, "To the extent that we're playing politics, it's the politics of letting people back home know where their senator is when it comes to solving this problem".
He also noted "reports that they have moved a number of people from Iraq and Syria to Libya," adding, "to the extent that it's happening that's striking.
The value to the review of these three studies was in adding to the extent of evidence, rather than adding details about practices' structure and functioning.
She added, "To the extent that questions have come up, we have answered them".
He added, "To the extent that today's hearing restores it — by removing immediate threat of vacating a rule — it is a good day".
But he added: "To the extent that we think he is not being tough enough, I think you'll see Congress coming in and potentially doing something".
And, he added, "to the extent that these are for the benefit of the participants, I don't think you want to do that.
But he added, "To the extent that this proposed law would ban the display of products to adult tobacco consumers, we believe it goes too far".
Oliver added: "To the extent the senator's letter is suggesting that there is no standard for a reconditioned and recertified helmet, that of course is clearly inaccurate.
I recommend that the serial publications should be continued or replaced by better ones (if any such appear) and that new books which promise to be of permanent value should be added to the extent that funds will permit.
Using the telecommunications shorthand "CLEC's" to refer to new local phone companies as competitive local exchange carriers, he added, "To the extent that CLEC's have been getting a free ride, that's going to stop".
