the SAT math includes 5-7 Alg II problems, so it is harder in that sense. However, for most kids the material is more recent, so in that case it may not appear as hard. Also, CR scores generally go up with another year of HS english, but at 80, you don't have much room to increase.
IMO, the real killer is fatigue. Try to take a couple of full length practice tests at home under ideal test conditions to acclimate your body and brain.