ejoi8 on "[Plugin: WooCommerce Weight Based Shipping] Weight Rate Charge skip Calculate"

Hi,

My first attempt using this plugin is awesome but some weird things happen when I try to set Multiple Weight Range (0.1-0.4 lbs | 0.4-1.0 lbs). At first everything is ok, but after I revert back to single Weight Range (0.1-1.0 lbs) option, I faced situation as below:

PRODUCT:
Product Price: 0
Product weight: 0.1 lbs

SHIPPING:
Weight: [0.1 – 1.1)
Cost: 10 + 3 per 0.1 lbs (from 0.1 lbs)

Situation Occur:
1 item add to cart = $10 (OK)
2 item add to cart = $13 (OK)
3 item add to cart = $19(suppose to be $16)
4 item add to cart = $22(suppose to be $19)
5 item add to cart = $22(suppose to be $21)
6 item add to cart = $28(suppose to be $24)

I try to play around to fix it but things get more confusing. Do you have any idea what possibility how this situation happen? I try to remove and reinstall the plugin and yet the problem is still occur. How can I "Reset" this plugin thru database?

https://wordpress.org/plugins/weight-based-shipping-for-woocommerce/

Update:
I try to change the weight scale from 0.1 lbs to 1 lbs.

PRODUCT:
Product Price: 0
Product weight: 1 lbs

SHIPPING:
Weight: [1 – 11)
Cost: 10 + 3 per 1 lbs (from 1 lbs)

Situation Occur:
1 item add to cart = $10 (OK)
2 item add to cart = $13 (OK)
3 item add to cart = $16 (OK)
4 item add to cart = $19 (OK)
5 item add to cart = $21 (OK)
6 item add to cart = $24 (OK)

Everything works fine if I scale up the weight. But, I need to use 0.1 lbs instead of 1 lbs in my product. I think maybe some sort of config setting have been stored in the database. I try to delete the woowbs_main_settings but the problem still the same. Please help me. Thank you in advance.