2x per week is prob unnecessary.. once per week may even be unnecessary depending how many carbs u eat the rest of the week per day.. at 100g per day u could go 14days .. i do understand the logic behind elevating ur carbs on heavy lift days to fuel ur workout and recovery.. i would suggest putting the xtra carbs in pre and post workout meals.. on 2000cals per day cut i wouldnt go over 150g carbs on those 2 days.. i would try to limit it to one..
personally i do legs 4x per week now and 2 of those days have zero starchy carbs.. IMO u would be fine at 100g...