Don't know how much PV they are doing now, but Hawaii Energy (not HECO) had several certified installers they trained, offered rebates for certain types of installations, was working with HECO to initiate a net-zero financing program that I don't think was rolled out (need to check), and did PV audits for the rate payer.
The audits involved 3 areas: location, conservation, and "right-sizing".
Location is important. The analysis took into account the max, min, avg temperatures throughout the year and number of cloudy days. not every town on the island experiences the same level of cloud cover due to mountains, valleys, etc. Using historical databases, they can tell how much sunlight you can expect to receive in a day, month or year. It really does vary based on a variety of environmental factors.
Conservation started with the largest energy sucks in most homes: hot water, AC and kitchen appliances. If you already have solar hot water, that greatly reduces the amount of PV you'll need. Same if you have the most efficient appliances for AC and refrigeration. If you have a second fridge, they have rebate programs to incentivize removing it. Those are usually old fridges that aren't as efficient as new ones.
Right-sizing means measuring the amount of energy being used at all hours to determine how much you can produce through PV and how much you need to receive from HECO and/or stored energy (battery capacity). Ex: If nobody is home for 8-10 hours during weekdays, then you don't need to generate as much power while the Sun shines 5 of 7 days. On weekends, there's probably more cooking and AC use, so that also gets included. If it turns out saving on installation will be better than not using commercial power for a couple of hours on the weekend, that needs to be factored in. You may be generating enough power and selling it back to HECO on weekdays that it totally offsets any extra HECO power used on weekends.
There are software tools available to monitor the generation and usage of your PV system. It's wise to evaluate and compare those apps so you will have the ability to maybe alter your usage to reduce loads at certain times. Like running the dishwasher and clothes washer when no one is home turning on lights, running the AC or cooking.
There are monitoring systems available now not related to a PV system that can track your energy use at home. It hooks up to your breaker box and records when you are using electricity and how much. Some have rented these from Hawaii Energy to do a 2-3 week audit so they know exactly what their usage is.
With some expert planning, the cost to install PV can be managed to give you what you need now plus an additional percentage for future needs.
BTW, if you have an EV, that needs to be factored in. Charging at night can drain batteries / increase use of HECO power. Charging in daytime might mean you need more generating capacity depending on total household usage.
If you're working with an installer that simply sells you enough panels to cover your roof with no analysis of usage, you should probably shop around. Start by contacting Hawaii Energy and ask if they can point you in the right direction. You paid for their services each time you paid an electric bill, so why not?
https://hawaiienergy.com/