The value of rice does not change whether it is harvested by 8 farmers with hands or 2 farmers with machines.

I suggest you read up on constant capital, variable capital and the tendency of the rate of profit to fall. This is an accessible article written in easy to follow language that explains this. The tl;dr is that the more you pay for raw materials and machines and the less you pay for labour, the lower the surplus value (and by extension profit) of a commodity is.

Furthermore, it can take the same number of hours to write a particular program, but that does not predict how useful or valuable a program will be.

The LTV doesn't deal with market price, it deals with the value of a commodity at equilibrium, meaning when supply matches demand.

It probably will be a good idea not to dismiss the LTV out of hand if you aren't very familiar with it.