OpenBrush follow-up delivery milestone 1(3 milestone for OpenBrush)

[xgreenx]

Milestone Delivery Checklist

• The milestone-delivery-template.md has been copied and updated.
• The invoice form 📝 has been filled out for this milestone.
• This pull request is being made by the same account as the accepted application.
• In case of acceptance, the payment will be transferred to the BTC/ETH payment address provided in the application.
• The delivery is according to the Guidelines for Milestone Deliverables.

Link to the application pull request: w3f/Grants-Program#621

We didn't fill the invoice form yet.
We generated more full changes than planned and it took on one week more.

From of our Grant:

We want to briefly(not full change, only minimal changes to reduce the size) implement them and provide a report(re-working data structure, reducing monomorphization, using dynamic dispatch in some cases).

In the description of the milestone, we mentioned that we're going to do "not full change,
only minimal changes to reduce the size", but we implemented them fully and it took more time.
Is it possible to increase payment for that milestone from 9,000 USD to 15,000?