Formulas from Petersen's Cthulhu Mythos - can they be Counterspelled?

Question

Formulas in Sandy Petersen's Cthulhu Mythos are similar to Rituals with a few key differences. Like Rituals they can be cast without a spell slot, and you can also use spells slots to cast them (generally more quickly, or potentially at a higher level). Unlike Rituals Formulas require Skill checks to cast, carry penalties for failure (and sometimes success), and can be cast by anyone, even non-casters.

The fluff around formulas contains the following:

Such a spell draws upon universal principles that allow them to function even for non-spellcasters. Formula magic uses science and mathematics beyond most mortal understanding to power the casting of highly specialized spells. Most formulas are held only in shunned books and in the minds of dangerous eccentrics who know more than is safe about the secrets of reality. Generally, these spells depend upon knowledge of the alien sciences, extradimensional mathematics, and incomprehensible iconography of the cosmic forces underlying the Mythos.

The consensus seems to be that Rituals are able to be counterspelled at any time during their casting; I don't see a reason why Formulas would necessarily be different, but there are enough differences that I'm left unsure.

Answer 1

Yes, they are still spells and are still cast

All throughout the chapter Formulas are still referred to as spells:

Certain spells in this chapter have a special tag:formula. Such a spell draws upon universal principles (…).

Generally, these spells depend upon knowledge of the alien sciences, extradimensional mathematics and incomprehensible iconography (…).

Casting as formula is still casting a spell:

A spell with the formula tag can be cast normally, [or] as a formula (…).

Casting a spell as a formula takes the normal casting time (…).

Formula spells can be learned and cast by anyone with the appropriate tools and knowledge.

Even character without the Spellcasting feature or Pact Magic feature can learn and cast spells as formulas.

These is just a few examples but the same wording is used anytime Formulas are referred to, this leads me to believe they are intended to be treated as regular spells for the purpose of Counterspell.