Version 1.1 work has begun

For those that may be interested, work on version 1.1 has begin.

The draft description for 1.1 is not complete and additional features may be added, such as a "free" shipping feature based on a minimal quantity.

DRAFT:

WordPress administrative users can create a multi-tiered flat rate shipping fee 
based on the total number of items in a WooCommerce cart. The store 
administrator can choose to apply this shipping method to all available 
countries that the store may ship to, or only specific countries.

There are four tiers, one for each USPS flat-rate box in this shipping method.
An additional tier that is additive to the final tier provides a per-item flat
rate for items beyond what fits in the last highest tier.

While the four tiers plus additional overflow tier is ideal for USPS flat-rate
box shipping, the pluggin is somewhat flexible.  Tiers 3 and 4 can be disabled
such that they are skipped.  The overflow tier will be additive to the enabled
highest tier.

Example 1: Default 4-Tier (all tiers enabled; suitable for USPS flat-rate)

  Tier|Max Qty| Cost
  ----+-------+------
    1 |   2   |$ 5.95
    2 |   4   |$12.65
    3 |  10   |$15.90
    4 |  15   |$17.90
    + | each  |$ 1.12

   such that cost for 20 items = $17.90 + 5 x $1.12

Example 2: Custom 2-Tier (tiers 3 and 4 disabled)

  Tier|Max Qty| Cost
  ----+-------+------
    1 |  10   |$ 7.00
    2 |  40   |$21.00
    3 |   disabled
    4 |   disabled
    + | each  |$ 3.50

  such that cost for 50 items = $21.00 + 10 x $3.50