One area of significant cooling loss is related to loss of underfloor pressures due to openings that are not sealed. It is very common for the facilities guys to cut the floor tiles so the IT crew can pass their cables through.
What frequently happens, especially in older data centers, is that holes are not plugged or closed up around the cables which results in cooling going to the wrong places. In my experience, I have been to many data centers where there just old tiles with cut outs in them sitting around the data centers.
You can stuff the hole with a fire retardant material or there is a product called Kold-Lok (developed by the guys at Uptime I believe) that can be used to close things off. As the prior answer indicated, you could have a CFD analysis completed for your raised floor, which will cost several thousand dollars and confirm your suspicion.
You can use the soft fire proof bags that are used to seal wall penetrations. These can be purchased in different sizes and can also be squashed in around the cables etc. While these are a very fine covered bag and will not allow the fire proof fill to escape care needs to be taken to ensure the tiles do not have sharp edges. If continually removed for adding cables etc careful observation needs to be taken to ensure tear's or worn areas do not occur.
Simple tin plate can also be used if it's under racks and you won't be standing on the cover.
OK, as I understand it, the panel on your UPS indicates the OUTPUT of the UPS is 200 kVA. Servers generally have a power factor of one, and all server input power is considered converted to heat that must be removed. Then
200 kVA x 1.0 p.f. = 200 kW converted to heat.
200 kW x 3414 BTUH/kW x 1 ton/12,000 BTUH = 56.89 tons of cooling required to remove heat of servers (+ PDU + switches + appliances + routers + storage etc).
Remember, if the data center roof is also the roof of the building and/or the data center walls are the outside walls of the building, you must add additional cooling to remove the solar load. I don't hae a rule of thumb for what that will be (you really should hire a consulting engineer to size the system).
Neither the raised floor nor the cabling will increase the cooling load, they will increase the fan static pressure required to deliver the conditioned air to the servers.
Yes, sealing holes in floor, instituting hot aisle-cold aisle arrangement, using thermal barriers to prevent mixing of room air with hot air, etc should improve system efficiency.