one size does not fit!

I initially purchased a 29 X 30 waist Khaki colored pant and was very pleased with it. Its was a hard to find size and fitted perfectly. Encouraged by this I went on to purcahse two more string and grey colored kahkis. Unfortunately, both were much more tighter than the earlier ones and when measured by tape its 28.3-28.5 waist. There seems to be too much variation in the waist size despite a being sold as a 29 waist. I will be very reluctant to buy this brand again...atleast not online.Material-wise its excellent....so 2 stars!