When he said that, he was with others separatist, like Nute Gunray. The interventions of the clone army is part of the plan, But, to make the plan work, it is imperative that the separatist thrust Dooku, so he simulated surprise.

The Clone war is essential to the rise of Sidious as the Emperor, and for the establishment of a new Sith Empire. But for that, he had to play the separatist's friend  :

As Tyranus, Dooku became a Humanocentrist. While he remained a connoisseur of alien art and antiquities, he secretly despised most if not all of the corrupt aliens on the Separatist Council, though he reserved a measure of respect for the Geonosian Poggle.

• Dooku article on Wookieepedia

When he said that, he was with other separatists, like Nute Gunray. The intervention of the clone army is part of the plan, but, to make the plan work, it is imperative that the separatists trust Dooku, so he simulated surprise.

The Clone War is essential to the rise of Sidious as the Emperor, and for the establishment of a new Sith Empire. But for that, he had to play the separatists' friend:

As Tyranus, Dooku became a Humanocentrist. While he remained a connoisseur of alien art and antiquities, he secretly despised most if not all of the corrupt aliens on the Separatist Council, though he reserved a measure of respect for the Geonosian Poggle.

• Dooku article on Wookieepedia

When he said that, he was with others separatist, like Nute Gunray. The interventions of the clone army is part of the plan, But, to make the plan work, it is imperative that the separatist thrust Dooku, so he simulated surprise.

The Clone war is essential to the rise of Sidious as the Emperor, and for the establishment of a new Sith Empire.

When he said that, he was with others separatist, like Nute Gunray. The interventions of the clone army is part of the plan, But, to make the plan work, it is imperative that the separatist thrust Dooku, so he simulated surprise.

The Clone war is essential to the rise of Sidious as the Emperor, and for the establishment of a new Sith Empire. But for that, he had to play the separatist's friend :

As Tyranus, Dooku became a Humanocentrist. While he remained a connoisseur of alien art and antiquities, he secretly despised most if not all of the corrupt aliens on the Separatist Council, though he reserved a measure of respect for the Geonosian Poggle.

• Dooku article on Wookieepedia