When piece measures 8 cm dec 1 st on each side of markers repeat dec when piece measures 12 cm Read DECREASE TIP 130142158174194214 sts

Could you correct the punctuation please?
When piece measures 8 cm, dec 1 st on each side of markers, repeat dec when piece measures 12 cm - Read DECREASE TIP = 130-142-158-174-194-214 sts.