2130 bourgaut metering

Hi. I have to reseed some canola. I picked the same setting I used previously and it have me 5 lb per ac. I was applying fert at same time. Now I'm applying just seed and my rate is all over. Way to low and even if I go to smaller sprockets it still is too low. I used a 42 tooth before. and now I'm on 35 and still not good should i throw seed in front tank and take off drive chain or to I adjust dual pressurization valve? Thank you

2130 bourgaut metering