When selecting the custom split amounts option, the entered amounts are not reconciled with the total bill amount.
We can therefore have a total amount of 20 for three participants with their individual amounts being 10, 11 and 13, which results in a total of 34.
I realise making the custom individual amounts prevail over the total amount or not is a matter of personal preference and convenience (both in UI/UX and development) and I am fine with it.
However, I think there should be an indication that the total amount entered above in the form is disregarded as soon as the custom split amounts option is selected. It could be with a popup message and/or greying the total amount.
An alternative functioning I can think of would be:
if the sum of custom individual amounts is bigger than the above-entered total, a blocking error message;
if the sum of custom individual amounts is lower than the above-entered total and one or more participants' field was not filled with a custom individual amount, then the remaining is evenly* split between them (excluding the participants whose field were already filled with a custom amount, which is therefore different from the option "even split with possible personal spendings");
if every participant's field was filled with a custom individual amount but their sum is lower than the total, the remaining is evenly* shared between all participants.
"Evenly" is the accurate term only if all the participants have an equal weight. I think in the cases mentioned above, the preset weights should be respected.
When selecting the custom split amounts option, the entered amounts are not reconciled with the total bill amount.
We can therefore have a total amount of 20 for three participants with their individual amounts being 10, 11 and 13, which results in a total of 34.
I realise making the custom individual amounts prevail over the total amount or not is a matter of personal preference and convenience (both in UI/UX and development) and I am fine with it.
However, I think there should be an indication that the total amount entered above in the form is disregarded as soon as the custom split amounts option is selected. It could be with a popup message and/or greying the total amount.
An alternative functioning I can think of would be:
if the sum of custom individual amounts is bigger than the above-entered total, a blocking error message;
if the sum of custom individual amounts is lower than the above-entered total and one or more participants' field was not filled with a custom individual amount, then the remaining is evenly* split between them (excluding the participants whose field were already filled with a custom amount, which is therefore different from the option "even split with possible personal spendings");
if every participant's field was filled with a custom individual amount but their sum is lower than the total, the remaining is evenly* shared between all participants.
"Evenly" is the accurate term only if all the participants have an equal weight. I think in the cases mentioned above, the preset weights should be respected.