Hello Maria,
Regarding 54.3, it's not exactly a mistake that the purchase of equipment appears on the cash budget since some countries operate under different accounting rules. Nevertheless, you should always refer to the financial budget to record cash flows related to the purchase of non-current assets. I think your mistake was there - you double counted the purchase of equipment when it was already reflected in the cash budget, that's why the financial investment is of 152.441,36€
Regarding 54.4, I think you are referring to the financial revenue of Quarter 4? In Quarter 3, the company gets interest in the amount of the financial investment, this is, the 441,36€ you referred. In Quarter 4, the outstanding investment is already larger - it's the 88.272 plus the additional 152.441,36, so you need to multiply the interest rate by that.