polling is underway to assess shareholder intentio, page-13

One of the problems that Tullow has is that they have limited time to get this vote away.

If they lose the first vote and decide to come back with a higher offer after the meeting, they run the risk that full Kingfisher results will be in by the time they get another vote completed. Added to that the likelihood that Ching remediation will also be underway, and they may have to raise the bid significantly to get a yes vote.

It may be cheaper for them to raise the bid a bit now rather than to have to raise it a lot later.