A Discussion
Soil Water Absorbency
To discuss soil Water Absorbency,
we need to reflect upon the Water Holding Capacity

The Water holding factor for various soil types has been studied and documented for many years.
Also known as "Available Moisture" it is listed in the chart below

The purpose for providing an "Absorbency Rating: is simply to compare the most absorbent soil type with the others listed within the Calculator.
The higher the Absorbecy Rating the easier for the Plant to both Breath and Drink.
The absorbency rating is calculated by multiplying a factor of the "Effective Capacity" of the soil by the "Water Holding Capacity" of that soil.
Effective Capacity the the ability of a particular soil to "accept" water into it's pores.
Water Holding Capacity is the ability of a soil to "hold onto" the water applied.

An example; Sand will "allow" a lot of water to be added, due to the large proportion of air space to soil particles, but Sand hasn't the ability to "hold onto that water". So; Sand winds up with a 16% absorbency. Clay does not allow much water to be added, due to the small proportion of air space to soil particle, yet it does hold onto water well. So; Clay has an Absorbency rating of 11%.

Drought tolerant plants should have dryer soil than Heavy water use plants when it is time to reapply moisture.

Due to these factors, the calculator specifies the different quantities of water. If watering a new plant with dry soil, then use the quantity of water specified for that.

Using a soil with a higher Absorbency rating, allows you to apply more water to the pot during each irrigation.
Consider; if (using sand) it's just going to run through,
or on the other hand (using clayey soil) it sit on top of the soil
The amount of water that can be applied will be much less.
An Exception: If using a slow draining soil, and using a very long run time, with very few emitters, more water can be applied. Here the water is being given extra time to be absorbed.
How many Minutes versus Gallons?
Remember "how many minutes" varies with the number and flow rate of the emitters you use.
Most emitters are rated in gallons or fractions of a gallon per hour

As shown here; 1/4 inch dripperline has "built-in" 0.75 gallon per hour emitters.
These are evenly spaced every 6 or 12 inches depending on which style used.
By cutting a specified length then adding a plug at the far end, you will get the correct number of emitters needed for the pot being watered.