You’re right, it was only once.
From the article:
*** In an interview with ABC News, Rooney also clarified statements made by Hamlin’s uncle, Dorrian Glenn, who said Tuesday that Hamlin had to be resuscitated twice — on the field and at the hospital. Rooney said that was a misunderstanding and that Hamlin was not resuscitated more than once.***
I tend to believe nothing from officials. The family member is probably much more honest.