CSS animation with incorrect time ratio

I'm trying to execute the animation below, which basically consists of raising the lock, making it rotate and then going down. I would like this to be done proportionately. However, even using a much lower percentage for the descent, the animation seems to execute the first two steps in 2s and the descent in the remaining 2s.

@keyframes float {
    0%,3% {

        transform: translatey(0px);
    }
    3%, 6% {

        transform: translatey(-4px);
    }
    
    6%, 30%{
        transform: rotateY(0deg) translatey(-4px);
    }
    30%, 94%{
        transform: rotateY(1080deg) translatey(-4px);
    }

    94%, 100%{
        transform: translatey(0px);
    }
}

.square {
    
    animation: float linear infinite;
    animation-duration: 4s;
}

div {
    perspective: 500px; 
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 44px;
}

.cadeado{
    background-image: url(https://www.qas.flyembraer.com/irj/go/km/docs/download_center/Anonymous/loading-sem-cadeado.jpg);
    width: 144px;
    height: 144px;
    align:center;
}

<div class="cadeado">
<div class ="square"><img src="https://www.qas.flyembraer.com/irj/go/km/docs/download_center/Anonymous/cadeado.jpg" alt="" align="center"></div>
</div>


I've tried setting the proportional % to 33% for each step but it still doesn't work

Solution

I have found that mirroring he animation to be helpful. Is this closer to what you were looking for?

@keyframes float {
    0%,10% {

        transform: translatey(0px);
    }
    10%, 20% {

        transform: translatey(-4px);
    }
    
    20%, 60%{
        transform: rotateY(0deg) translatey(-4px);
    }
    60%, 80%{
        transform: rotateY(1080deg) translatey(-4px);
    }
    80%, 90% {
        transform: translatey(-4px);
    }

    90%, 100%{
        transform: translatey(0px);
    }
}

.square {
    
    animation: float linear infinite;
    animation-duration: 5s;
}

div {
    perspective: 500px; 
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 44px;
}

.cadeado{
    background-image: url(https://www.qas.flyembraer.com/irj/go/km/docs/download_center/Anonymous/loading-sem-cadeado.jpg);
    width: 144px;
    height: 144px;
    align:center;
}

<div class="cadeado">
<div class ="square"><img src="https://www.qas.flyembraer.com/irj/go/km/docs/download_center/Anonymous/cadeado.jpg" alt="" align="center"></div>
</div>